2003 Audi RS6 vs. 2006 BMW 645
To start off, 2006 BMW 645 is newer by 3 year(s). Which means there will be less support and parts availability for 2003 Audi RS6. In addition, the cost of maintenance, including insurance, on 2003 Audi RS6 would be higher. At 4,398 cc (8 cylinders), 2006 BMW 645 is equipped with a bigger engine. In terms of performance, 2003 Audi RS6 (444 HP @ 6300 RPM) has 116 more horse power than 2006 BMW 645. (328 HP @ 6100 RPM). In normal driving conditions, 2003 Audi RS6 should accelerate faster than 2006 BMW 645. With that said, vehicle weight also plays an important factor in acceleration. 2003 Audi RS6 weights approximately 95 kg more than 2006 BMW 645. So despite on having greater horse power, its additional weight may have an impact towards its acceleration in comparison.
Because 2003 Audi RS6 is four wheel drive (4WD), it will have significant more traction and grip than 2006 BMW 645. In wet, icy, snow, or gravel driving conditions, 2003 Audi RS6 will offer significantly more control. With that said, do keep in mind that many other factors such as speed and the wear on your tires can also have significant impact on traction and control. Let's talk about torque, 2003 Audi RS6 (560 Nm @ 1950 RPM) has 110 more torque (in Nm) than 2006 BMW 645. (450 Nm @ 3600 RPM). This means 2003 Audi RS6 will have an easier job in driving up hills or pulling heavy equipment than 2006 BMW 645. 2006 BMW 645 has automatic transmission and 2003 Audi RS6 has manual transmission. 2003 Audi RS6 will offer better control over acceleration and deceleration in addition to better fuel efficiency overall. 2006 BMW 645 will be easier to drive especially in heavy traffic.
Compare all specifications:
| 2003 Audi RS6 | 2006 BMW 645 | |
| Make | Audi | BMW |
| Model | RS6 | 645 |
| Year Released | 2003 | 2006 |
| Body Type | Station Wagon | Convertible |
| Engine Position | Front | Front |
| Engine Size | 4163 cc | 4398 cc |
| Engine Cylinders | 8 cylinders | 8 cylinders |
| Engine Type | V | V |
| Valves per Cylinder | 5 valves | 4 valves |
| Horse Power | 444 HP | 328 HP |
| Engine RPM | 6300 RPM | 6100 RPM |
| Torque | 560 Nm | 450 Nm |
| Torque RPM | 1950 RPM | 3600 RPM |
| Engine Bore Size | 84.5 mm | 92 mm |
| Engine Stroke Size | 93 mm | 82.7 mm |
| Engine Compression Ratio | 9.3:1 | 10.0:1 |
| Fuel Type | Gasoline | Gasoline - Premium |
| Top Speed | 250 km/hour | 250 km/hour |
| Drive Type | 4WD | Rear |
| Transmission Type | Manual | Automatic |
| Number of Seats | 5 seats | 4 seats |
| Number of Doors | 5 doors | 2 doors |
| Vehicle Weight | 1910 kg | 1815 kg |
| Vehicle Length | 4860 mm | 4830 mm |
| Vehicle Width | 1860 mm | 1860 mm |
| Vehicle Height | 1460 mm | 1380 mm |
| Wheelbase Size | 2760 mm | 2790 mm |
| Fuel Consumption Overall | 14.6 L/100km | 12.8 L/100km |
| Fuel Tank Capacity | 82 L | 70 L |
