2006 Audi A4 vs. 2003 BMW 645
To start off, 2006 Audi A4 is newer by 3 year(s). Which means there will be less support and parts availability for 2003 BMW 645. In addition, the cost of maintenance, including insurance, on 2003 BMW 645 would be higher. At 4,398 cc (8 cylinders), 2003 BMW 645 is equipped with a bigger engine. In terms of performance, 2003 BMW 645 (325 HP @ 6100 RPM) has 73 more horse power than 2006 Audi A4. (252 HP @ 6500 RPM) In normal driving conditions, 2003 BMW 645 should accelerate faster than 2006 Audi A4. With that said, vehicle weight also plays an important factor in acceleration. 2003 BMW 645 weights approximately 100 kg more than 2006 Audi A4. So despite on having greater horse power, its additional weight may have an impact towards its acceleration in comparison.
Because 2006 Audi A4 is four wheel drive (4WD), it will have significant more traction and grip than 2003 BMW 645. In wet, icy, snow, or gravel driving conditions, 2006 Audi A4 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 BMW 645 (450 Nm @ 3600 RPM) has 120 more torque (in Nm) than 2006 Audi A4. (330 Nm @ 3250 RPM). This means 2003 BMW 645 will have an easier job in driving up hills or pulling heavy equipment than 2006 Audi A4.
Compare all specifications:
| 2006 Audi A4 | 2003 BMW 645 | |
| Make | Audi | BMW |
| Model | A4 | 645 |
| Year Released | 2006 | 2003 |
| Body Type | Station Wagon | Coupe |
| Engine Position | Front | Front |
| Engine Size | 3123 cc | 4398 cc |
| Engine Cylinders | 6 cylinders | 8 cylinders |
| Engine Type | V | V |
| Valves per Cylinder | 4 valves | 4 valves |
| Horse Power | 252 HP | 325 HP |
| Engine RPM | 6500 RPM | 6100 RPM |
| Torque | 330 Nm | 450 Nm |
| Torque RPM | 3250 RPM | 3600 RPM |
| Engine Bore Size | 84.5 mm | 92 mm |
| Engine Stroke Size | 92.8 mm | 82.7 mm |
| Engine Compression Ratio | 12.5:1 | 10.5:1 |
| Top Speed | 245 km/hour | 250 km/hour |
| Acceleration 0-100mph | 7 seconds | 5.9 seconds |
| Drive Type | 4WD | Rear |
| Number of Seats | 5 seats | 4 seats |
| Number of Doors | 5 doors | 2 doors |
| Vehicle Weight | 1590 kg | 1690 kg |
| Vehicle Length | 4590 mm | 4830 mm |
| Vehicle Width | 1780 mm | 1860 mm |
| Vehicle Height | 1430 mm | 1380 mm |
| Wheelbase Size | 2650 mm | 2890 mm |
| Fuel Consumption Overall | 9.6 L/100km | 11.7 L/100km |
| Fuel Tank Capacity | 70 L | 70 L |
