Car comparison

BMW 6 Series (E63) 645CivsCadillac XLR 4.6 i V8 32V

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

New comparison

BMW 6 Series (E63)

645Ci

333 hp4398 ccGasolineRWDAutomaticNaturally aspiratedCoupe2003-2005
VS

Cadillac XLR

4.6 i V8 32V

325 hp4565 ccGasolineRWDAutomaticNaturally aspiratedCoupe2003-2009

Comparison overview

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

Best choices

BMW 6 Series (E63) 645Ci

  • Quickest 0-100 km/h
    5.8 s
  • Fastest top speed
    265 km/h
    165 mph Unrestricted
    250 km/h
    155 mph Restricted
  • Most powerful
    333 hp
    248 kW
  • Highest torque
    450 Nm
    332 lb-ft
  • Best power-to-weight
    196 hp/t
    147 kW/t
    5.1 kg/hp
  • Lowest combined fuel consumption
    10.9 L/100 km
    21.6 mpg US
    25.9 mpg UK
  • Lowest city consumption
    16.1 L/100 km
    14.6 mpg US
    17.5 mpg UK
  • Lowest highway consumption
    8.0 L/100 km
    29.4 mpg US
    35.3 mpg UK
  • Lowest CO2 emissions
    264 g/km
  • Best estimated range
    642 km
    399 mi
  • Largest trunk
    450 L
  • Best overall score
    63/100
  • Best performance score
    68/100
  • Best economy score
    78/100
  • Best practicality score
    53/100

Specification comparison

Specification comparison
ModelBMW6 Series (E63)645CiCadillacXLR4.6 i V8 32V
Power
333hp248kW
325hp242kW
Torque
450Nm332lb-ft
420Nm310lb-ft
Curb weight
1,695kg3,737lb
1,690kg3,726lb
Gross weight
2,065kg4,553lb
-
Top speed
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Calculated
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Calculated
To 99% top speed
79.6s99% target: 262 km/h / 163 mph
Calculated
81.2s99% target: 262 km/h / 163 mph
Calculated
0-100 km/h
5.8s
5.9s
0-200 km/h
20.3s
Calculated
20.7s
Calculated
0-60 mph
5.5s
Calculated
5.6s
Calculated
Fuel consumption
10.9L/100 km21.6mpg US25.9mpg UK
12.3L/100 km19.1mpg US23.0mpg UK
Fuel consumption city
16.1L/100 km14.6mpg US17.5mpg UK
18.2L/100 km12.9mpg US15.5mpg UK
Fuel consumption highway
8L/100 km29.4mpg US35.3mpg UK
9L/100 km26.1mpg US31.4mpg UK
Quarter mile
13.9s
Calculated
14.0s
Calculated
Power-to-weight
196hp/t147kW/t89hp/1000 lb
Calculated
192hp/t143kW/t87hp/1000 lb
Calculated
Torque-to-weight
265Nm/t178lb-ft/ton
Calculated
249Nm/t166lb-ft/ton
Calculated
Estimated range
642km399mi
Calculated
553km344mi
Calculated
Displacement
4,398cc268cu in
4,565cc279cu in
Length
4,820mm190in
4,513mm178in
Width
1,855mm73in
1,836mm72in
Height
1,373mm54in
1,279mm50in
Wheelbase
2,780mm109in
2,685mm106in
Front track
1,558mm61in
1,580mm62in
Rear track
1,592mm63in
1,580mm62in
Trunk volume
450L
125L
Max trunk volume-
328L
Doors
2
2
Seats
4
2
Fuel tank
70L
68L
CO2 emissions
264g/km
291g/km

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 6 Series (E63) 645CiCadillac XLR 4.6 i V8 32VPowerTorque
  • BMW 6 Series (E63) 645Ci: Power / Torque
  • Cadillac XLR 4.6 i V8 32V: Power / Torque
Dyno simulation data table
VehiclePeak power RPMPeak torque RPMMax engine speed
BMW6 Series (E63)645Ci6,100 rpm3,600 rpm6,350 rpm
CadillacXLR4.6 i V8 32V6,400 rpm4,400 rpm6,650 rpm

Acceleration curve

Estimated speed over time for selected vehicles.

Acceleration and drag-race table
MetricBMW6 Series (E63)645CiCadillacXLR4.6 i V8 32V
Acceleration checkpoints
0-60 mph
0-97 km/h
5.5 s
5.6 s
0-100 km/h
0-62 mph
5.8 s
5.9 s
0-200 km/h
0-124 mph
20.3 s
20.7 s
Top speed
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Likely limited
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Likely limited
Drag race simulation
60 ft
18 m
2.3 s
2.3 s
330 ft
101 m
6.1 s
6.1 s
1/8 mile
201 m
9.1 s
9.2 s
1000 ft
305 m
11.7 s
11.8 s
1/4 mile
402 m
13.9 s
14.0 s
Trap speed
1/4 mile
402 m
169 km/h
105 mph
168 km/h
104 mph

Power comparison

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

Chart data table
VehicleValue
BMW6 Series (E63)645Ci
333 hp
248 kW
CadillacXLR4.6 i V8 32V
325 hp
242 kW

BMW 6 Series (E63) 645Ci has 8 hp more than Cadillac XLR 4.6 i V8 32V.

The biggest power difference is between Cadillac XLR 4.6 i V8 32V and BMW 6 Series (E63) 645Ci: 8 hp (6 kW).

Torque comparison

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

Chart data table
VehicleValue
BMW6 Series (E63)645Ci
450 Nm
332 lb-ft
CadillacXLR4.6 i V8 32V
420 Nm
310 lb-ft

Curb weight comparison

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

Chart data table
VehicleValue
BMW6 Series (E63)645Ci
1,695 kg
3,737 lb
CadillacXLR4.6 i V8 32V
1,690 kg
3,726 lb

Top speed without limiter comparison

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

Chart data table
VehicleValue
BMW6 Series (E63)645Ci
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
CadillacXLR4.6 i V8 32V
Unrestricted
265 km/h165 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
BMW6 Series (E63)645Ci5.8 s
CadillacXLR4.6 i V8 32V5.9 s

The biggest 0-100 km/h difference is between BMW 6 Series (E63) 645Ci and Cadillac XLR 4.6 i V8 32V: 0.1 s.

Fuel consumption comparison

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

Chart data table
VehicleValue
BMW6 Series (E63)645Ci
10.9 L/100 km
21.6 mpg US
25.9 mpg UK
CadillacXLR4.6 i V8 32V
12.3 L/100 km
19.1 mpg US
23.0 mpg UK

The biggest fuel consumption difference is between BMW 6 Series (E63) 645Ci and Cadillac XLR 4.6 i V8 32V: 1.4 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
BMW6 Series (E63)645Ci
196 hp/t
147 kW/t
5.1 kg/hp
CadillacXLR4.6 i V8 32V
192 hp/t
143 kW/t
5.2 kg/hp

Estimated range comparison

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

Chart data table
VehicleValue
BMW6 Series (E63)645Ci
642 km
399 mi
CadillacXLR4.6 i V8 32V
553 km
344 mi

Performance spider chart

Radar chart comparing normalized performance and fuel-consumption scores.

Chart data table
VehiclePowerAccelerationTop speed
BMW6 Series (E63)645Ci
333 hp
248 kW
5.8 s
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
CadillacXLR4.6 i V8 32V
325 hp
242 kW
5.9 s
Unrestricted
265 km/h165 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
BMW6 Series (E63)645Ci
Power
333 hp
248 kW
0-100 km/h5.8 s
Top speed
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Doors/seats
2 doors
4 seats
Trunk
450 L
15.9 cu ft
Length
4,820 mm
189.8 in
Height
1,373 mm
54.1 in
CadillacXLR4.6 i V8 32V
Power
325 hp
242 kW
0-100 km/h5.9 s
Top speed
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Doors/seats
2 doors
2 seats
Trunk
125 L
4.4 cu ft
Length
4,513 mm
177.7 in
Height
1,279 mm
50.4 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
BMW6 Series (E63)645Ci
Power
333 hp
248 kW
0-100 km/h5.8 s
Top speed
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
10.9 L/100 km
21.6 mpg US
25.9 mpg UK
CadillacXLR4.6 i V8 32V
Power
325 hp
242 kW
0-100 km/h5.9 s
Top speed
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
12.3 L/100 km
19.1 mpg US
23.0 mpg UK

BMW 6 Series (E63) 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
BMW6 Series (E63)645Ci
10.9 L/100 km
21.6 mpg US
25.9 mpg UK
5.8 s
CadillacXLR4.6 i V8 32V
12.3 L/100 km
19.1 mpg US
23.0 mpg UK
5.9 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
BMW6 Series (E63)645Ci
196 hp/t
147 kW/t
5.1 kg/hp
10.9 L/100 km
21.6 mpg US
25.9 mpg UK
CadillacXLR4.6 i V8 32V
192 hp/t
143 kW/t
5.2 kg/hp
12.3 L/100 km
19.1 mpg US
23.0 mpg UK

Detailed score breakdown

Detailed score breakdown
VehicleBMW6 Series (E63)645CiCadillacXLR4.6 i V8 32V
Power
333 hp
248 kW
325 hp
242 kW
Torque
450 Nm
332 lb-ft
420 Nm
310 lb-ft
Acceleration
5.8 s
5.9 s
Top speed
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Lightness
1,695 kg
3,737 lb
1,690 kg
3,726 lb
Fuel consumption
10.9 L/100 km
21.6 mpg US
25.9 mpg UK
12.3 L/100 km
19.1 mpg US
23.0 mpg UK
Practicality
Doors/seats
2 doors
4 seats
Trunk
450 L
15.9 cu ft
Length
4,820 mm
189.8 in
Height
1,373 mm
54.1 in
Doors/seats
2 doors
2 seats
Trunk
125 L
4.4 cu ft
Length
4,513 mm
177.7 in
Height
1,279 mm
50.4 in
Range score
642 km
399 mi
553 km
344 mi
CO2 score
264 g/km
291 g/km
Trunk score
450 L
15.9 cu ft
125 L
4.4 cu ft
Power-to-weight score
196 hp/t
147 kW/t
5.1 kg/hp
192 hp/t
143 kW/t
5.2 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 6 Series (E63) 645CiCadillac XLR 4.6 i V8 32V
Consumption10.9 L/100 km21.6 mpg US25.9 mpg UK12.3 L/100 km19.1 mpg US23 mpg UK
Cost / 100 km19.08 LC100 km21.53 LC100 km
Cost / 100 mi30.70 LC100 mi34.64 LC100 mi
Annual fuel used1,635 L432 US gal360 UK gal1,845 L487 US gal406 UK gal
Annual fuel cost2,861 LC/year3,229 LC/year

Head-to-head comparisons

BMW 6 Series (E63) 645Ci

  • Has 8 hp more
  • Has 30 Nm more
  • Is 0.1 s quicker from 0-100 km/h
  • Uses 1.4 L/100 km less fuel
  • Has 4 hp/t better power-to-weight
  • Has 89 km (56 mi) more estimated range
  • Has 325 L more trunk volume
  • Emits 27 g/km less CO2

Pros

  • Quickest 0-100 km/h in this comparison
  • Highest top speed
  • Most powerful
  • Highest torque
  • Lowest combined fuel consumption
  • Best power-to-weight ratio
  • Best estimated range
  • Largest trunk

Cons

  • Heaviest

Cadillac XLR 4.6 i V8 32V

  • Is 5 kg lighter

Pros

  • Lightest

Cons

  • Slowest 0-100 km/h
  • Lowest power
  • Highest combined fuel consumption
  • Smallest trunk
  • Highest CO2 emissions

Choose cars to compare

Brand
Model
Generation
Engine or modification
BMW 6 Series (E63) 645Ci
Cadillac XLR 4.6 i V8 32V
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