Car comparison

BMW M3 Convertible (E46) 3.2i 24VvsBMW 6 Series Convertible (E64) 645Ci

Compare specs, acceleration, fuel consumption, dimensions, practicality, and estimated running costs side by side.

New comparison

BMW M3 Convertible (E46)

3.2i 24V

343 hp3246 ccGasolineRWDManualNaturally aspiratedCabriolet / convertible2001-2006
VS

BMW 6 Series Convertible (E64)

645Ci

333 hp4398 ccGasolineRWDAutomaticNaturally aspiratedCabriolet / convertible2003-2005

Comparison overview

Use the estimates as comparison hints and verify exact figures before making decisions.

Best choices

BMW M3 Convertible (E46) 3.2i 24V

  • Quickest 0-100 km/h
    5.5 s
  • Fastest top speed
    260 km/h
    162 mph Unrestricted
    250 km/h
    155 mph Restricted
  • Most powerful
    343 hp
    256 kW
  • Lightest
    1,655 kg
    3,649 lb
  • Best power-to-weight
    207 hp/t
    155 kW/t
    4.8 kg/hp
  • Largest trunk
    300 L
  • Best overall score
    59/100
  • Best performance score
    66/100

BMW 6 Series Convertible (E64) 645Ci

  • Highest torque
    450 Nm
    332 lb-ft
  • Lowest combined fuel consumption
    11.5 L/100 km
    20.5 mpg US
    24.6 mpg UK
  • Lowest city consumption
    16.8 L/100 km
    14.0 mpg US
    16.8 mpg UK
  • Lowest highway consumption
    8.5 L/100 km
    27.7 mpg US
    33.2 mpg UK
  • Best estimated range
    609 km
    378 mi
  • Best economy score
    76/100
  • Best practicality score
    45/100

Specification comparison

Specification comparison
ModelBMWM3 Convertible (E46)3.2i 24VBMW6 Series Convertible (E64)645Ci
Power
343hp256kW
333hp248kW
Torque
365Nm269lb-ft
450Nm332lb-ft
Curb weight
1,655kg3,649lb
1,820kg4,012lb
Gross weight
2,100kg4,630lb
2,220kg4,894lb
Top speed
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
Calculated
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
Calculated
To 99% top speed
76.2s99% target: 257 km/h / 160 mph
Calculated
87.8s99% target: 257 km/h / 160 mph
Calculated
0-100 km/h
5.5s
6.2s
0-200 km/h
20.0s
Calculated
22.8s
Calculated
0-60 mph
5.2s
Calculated
5.9s
Calculated
Fuel consumption
12.1L/100 km19.4mpg US23.3mpg UK
11.5L/100 km20.5mpg US24.6mpg UK
Fuel consumption city
17.9L/100 km13.1mpg US15.8mpg UK
16.8L/100 km14mpg US16.8mpg UK
Fuel consumption highway
8.8L/100 km26.7mpg US32.1mpg UK
8.5L/100 km27.7mpg US33.2mpg UK
Quarter mile
13.6s
Calculated
14.3s
Calculated
Power-to-weight
207hp/t155kW/t94hp/1000 lb
Calculated
183hp/t136kW/t83hp/1000 lb
Calculated
Torque-to-weight
221Nm/t148lb-ft/ton
Calculated
247Nm/t165lb-ft/ton
Calculated
Estimated range
521km324mi
Calculated
609km378mi
Calculated
Displacement
3,246cc198cu in
4,398cc268cu in
Length
4,492mm177in
4,820mm190in
Width
1,780mm70in
1,855mm73in
Height
1,363mm54in
1,373mm54in
Wheelbase
2,731mm108in
2,780mm109in
Front track
1,508mm59in
1,558mm61in
Rear track
1,525mm60in
1,592mm63in
Trunk volume
300L
300L
Max trunk volume-
350L
Doors
2
2
Seats
4
4
Fuel tank
63L
70L

Performance charts

Use the estimates as comparison hints and verify exact figures before making decisions.

Dyno simulation

Estimated stock-style power and torque curves by engine speed.

BMW M3 Convertible (E46) 3.2i 24VBMW 6 Series Convertible (E64) 645CiPowerTorque
  • BMW M3 Convertible (E46) 3.2i 24V: Power / Torque
  • BMW 6 Series Convertible (E64) 645Ci: Power / Torque
Dyno simulation data table
VehiclePeak power RPMPeak torque RPMMax engine speed
BMWM3 Convertible (E46)3.2i 24V7,900 rpm4,900 rpm8,150 rpm
BMW6 Series Convertible (E64)645Ci6,100 rpm3,600 rpm6,350 rpm

Acceleration curve

Estimated speed over time for selected vehicles.

Acceleration and drag-race table
MetricBMWM3 Convertible (E46)3.2i 24VBMW6 Series Convertible (E64)645Ci
Acceleration checkpoints
0-60 mph
0-97 km/h
5.2 s
5.9 s
0-100 km/h
0-62 mph
5.5 s
6.2 s
0-200 km/h
0-124 mph
20.0 s
22.8 s
Top speed
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
Likely limited
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
Likely limited
Drag race simulation
60 ft
18 m
2.2 s
2.4 s
330 ft
101 m
5.9 s
6.2 s
1/8 mile
201 m
8.9 s
9.3 s
1000 ft
305 m
11.5 s
12.0 s
1/4 mile
402 m
13.6 s
14.3 s
Trap speed
1/4 mile
402 m
170 km/h
105 mph
163 km/h
101 mph

Power comparison

Bar comparison chart for Power. Higher is better · hp / kW

Chart data table
VehicleValue
BMWM3 Convertible (E46)3.2i 24V
343 hp
256 kW
BMW6 Series Convertible (E64)645Ci
333 hp
248 kW

BMW M3 Convertible (E46) 3.2i 24V has 10 hp more than BMW 6 Series Convertible (E64) 645Ci.

The biggest power difference is between BMW 6 Series Convertible (E64) 645Ci and BMW M3 Convertible (E46) 3.2i 24V: 10 hp (7 kW).

Torque comparison

Bar comparison chart for Torque. Higher is better · Nm / lb-ft

Chart data table
VehicleValue
BMWM3 Convertible (E46)3.2i 24V
365 Nm
269 lb-ft
BMW6 Series Convertible (E64)645Ci
450 Nm
332 lb-ft

Curb weight comparison

Bar comparison chart for Curb weight. Lower is better · kg / lb

Chart data table
VehicleValue
BMWM3 Convertible (E46)3.2i 24V
1,655 kg
3,649 lb
BMW6 Series Convertible (E64)645Ci
1,820 kg
4,012 lb

Top speed without limiter comparison

Bar comparison chart for Top speed without limiter. Higher is better · km/h / mph

Chart data table
VehicleValue
BMWM3 Convertible (E46)3.2i 24V
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
BMW6 Series Convertible (E64)645Ci
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph

0-100 km/h comparison

Bar comparison chart for 0-100 km/h. Lower is better · seconds

Chart data table
VehicleValue
BMWM3 Convertible (E46)3.2i 24V5.5 s
BMW6 Series Convertible (E64)645Ci6.2 s

The biggest 0-100 km/h difference is between BMW M3 Convertible (E46) 3.2i 24V and BMW 6 Series Convertible (E64) 645Ci: 0.7 s.

Fuel consumption comparison

Bar comparison chart for Fuel consumption. Lower is better · L/100 km / mpg US / mpg UK

Chart data table
VehicleValue
BMWM3 Convertible (E46)3.2i 24V
12.1 L/100 km
19.4 mpg US
23.3 mpg UK
BMW6 Series Convertible (E64)645Ci
11.5 L/100 km
20.5 mpg US
24.6 mpg UK

The biggest fuel consumption difference is between BMW 6 Series Convertible (E64) 645Ci and BMW M3 Convertible (E46) 3.2i 24V: 0.6 L/100 km.

Power-to-weight comparison

Bar comparison chart for Power-to-weight. Higher is better · hp/t / kW/t

Chart data table
VehicleValue
BMWM3 Convertible (E46)3.2i 24V
207 hp/t
155 kW/t
4.8 kg/hp
BMW6 Series Convertible (E64)645Ci
183 hp/t
136 kW/t
5.5 kg/hp

Estimated range comparison

Bar comparison chart for Estimated range. Higher is better · km / mi

Chart data table
VehicleValue
BMWM3 Convertible (E46)3.2i 24V
521 km
324 mi
BMW6 Series Convertible (E64)645Ci
609 km
378 mi

Performance spider chart

Radar chart comparing normalized performance and fuel-consumption scores.

Chart data table
VehiclePowerAccelerationTop speed
BMWM3 Convertible (E46)3.2i 24V
343 hp
256 kW
5.5 s
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
BMW6 Series Convertible (E64)645Ci
333 hp
248 kW
6.2 s
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph

Most attractive quadrant

Scatter chart with performance score on the X axis and practicality score on the Y axis.

Chart data table
VehiclePerformance scorePracticality score
BMWM3 Convertible (E46)3.2i 24V
Power
343 hp
256 kW
0-100 km/h5.5 s
Top speed
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
Doors/seats
2 doors
4 seats
Trunk
300 L
10.6 cu ft
Length
4,492 mm
176.9 in
Height
1,363 mm
53.7 in
BMW6 Series Convertible (E64)645Ci
Power
333 hp
248 kW
0-100 km/h6.2 s
Top speed
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
Doors/seats
2 doors
4 seats
Trunk
300 L
10.6 cu ft
Length
4,820 mm
189.8 in
Height
1,373 mm
54.1 in

Performance vs fuel economy

Cars closer to the top-right corner combine stronger performance with better fuel economy scores.

Performance vs fuel economy data table
VehiclePerformance scoreFuel economy score
BMWM3 Convertible (E46)3.2i 24V
Power
343 hp
256 kW
0-100 km/h5.5 s
Top speed
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
12.1 L/100 km
19.4 mpg US
23.3 mpg UK
BMW6 Series Convertible (E64)645Ci
Power
333 hp
248 kW
0-100 km/h6.2 s
Top speed
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
11.5 L/100 km
20.5 mpg US
24.6 mpg UK

BMW 6 Series Convertible (E64) 645Ci is closest to the top-right balance target for performance and fuel economy.

Acceleration vs fuel consumption

Cars closer to the lower-left corner offer a better mix of quick acceleration and low fuel consumption.

Acceleration vs fuel consumption data table
VehicleFuel consumption, L/100 km0-100 km/h, s
BMWM3 Convertible (E46)3.2i 24V
12.1 L/100 km
19.4 mpg US
23.3 mpg UK
5.5 s
BMW6 Series Convertible (E64)645Ci
11.5 L/100 km
20.5 mpg US
24.6 mpg UK
6.2 s

Power-to-weight vs fuel consumption

The shaded area favors higher power-to-weight with lower combined fuel consumption.

Power-to-weight vs fuel consumption data table
VehiclePower-to-weight, hp/tFuel consumption, L/100 km
BMWM3 Convertible (E46)3.2i 24V
207 hp/t
155 kW/t
4.8 kg/hp
12.1 L/100 km
19.4 mpg US
23.3 mpg UK
BMW6 Series Convertible (E64)645Ci
183 hp/t
136 kW/t
5.5 kg/hp
11.5 L/100 km
20.5 mpg US
24.6 mpg UK

Detailed score breakdown

Detailed score breakdown
VehicleBMWM3 Convertible (E46)3.2i 24VBMW6 Series Convertible (E64)645Ci
Power
343 hp
256 kW
333 hp
248 kW
Torque
365 Nm
269 lb-ft
450 Nm
332 lb-ft
Acceleration
5.5 s
6.2 s
Top speed
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
Lightness
1,655 kg
3,649 lb
1,820 kg
4,012 lb
Fuel consumption
12.1 L/100 km
19.4 mpg US
23.3 mpg UK
11.5 L/100 km
20.5 mpg US
24.6 mpg UK
Practicality
Doors/seats
2 doors
4 seats
Trunk
300 L
10.6 cu ft
Length
4,492 mm
176.9 in
Height
1,363 mm
53.7 in
Doors/seats
2 doors
4 seats
Trunk
300 L
10.6 cu ft
Length
4,820 mm
189.8 in
Height
1,373 mm
54.1 in
Range score
521 km
324 mi
609 km
378 mi
Trunk score
300 L
10.6 cu ft
300 L
10.6 cu ft
Power-to-weight score
207 hp/t
155 kW/t
4.8 kg/hp
183 hp/t
136 kW/t
5.5 kg/hp
Overall
Fixed score
Fixed score

Fuel cost and annual usage

Estimate running costs from combined consumption, your annual distance, and the fuel price in your local currency.

Enter the fuel price in your local currency, for example €/L, $/gal, £/L or any other local currency.

LC = Local Currency

Fuel cost and annual usage
VehicleBMW M3 Convertible (E46) 3.2i 24VBMW 6 Series Convertible (E64) 645Ci
Consumption12.1 L/100 km19.4 mpg US23.3 mpg UK11.5 L/100 km20.5 mpg US24.6 mpg UK
Cost / 100 km21.18 LC100 km20.13 LC100 km
Cost / 100 mi34.08 LC100 mi32.39 LC100 mi
Annual fuel used1,815 L479 US gal399 UK gal1,725 L456 US gal379 UK gal
Annual fuel cost3,176 LC/year3,019 LC/year

Head-to-head comparisons

BMW M3 Convertible (E46) 3.2i 24V

  • Has 10 hp more
  • Is 165 kg lighter
  • Is 0.7 s quicker from 0-100 km/h
  • Has 24 hp/t better power-to-weight

Pros

  • Quickest 0-100 km/h in this comparison
  • Highest top speed
  • Most powerful
  • Lightest
  • Best power-to-weight ratio
  • Largest trunk

Cons

  • Highest combined fuel consumption

BMW 6 Series Convertible (E64) 645Ci

  • Has 85 Nm more
  • Uses 0.6 L/100 km less fuel
  • Has 88 km (55 mi) more estimated range

Pros

  • Highest torque
  • Lowest combined fuel consumption
  • Best estimated range

Cons

  • Slowest 0-100 km/h
  • Lowest power
  • Heaviest

Choose cars to compare

Brand
Model
Generation
Engine or modification
BMW M3 Convertible (E46) 3.2i 24V
BMW 6 Series Convertible (E64) 645Ci
Compare selected cars
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