2006 BMW 523 vs. 2004 BMW 645
To start off, 2006 BMW 523 is newer by 2 year(s). Which means there will be less support and parts availability for 2004 BMW 645. In addition, the cost of maintenance, including insurance, on 2004 BMW 645 would be higher. At 4,392 cc (8 cylinders), 2004 BMW 645 is equipped with a bigger engine. In terms of performance, 2004 BMW 645 (322 HP @ 7400 RPM) has 147 more horse power than 2006 BMW 523. (175 HP @ 5800 RPM) In normal driving conditions, 2004 BMW 645 should accelerate faster than 2006 BMW 523. With that said, vehicle weight also plays an important factor in acceleration. 2004 BMW 645 weights approximately 83 kg more than 2006 BMW 523. So despite on having greater horse power, its additional weight may have an impact towards its acceleration in comparison.
Both vehicles are rear wheel drive (RWD) - it offers better handling in dry conditions; in addition, if you are looking to drift, both vehicles do the job better than front wheel drive vehicles. 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, 2004 BMW 645 (447 Nm) has 217 more torque (in Nm) than 2006 BMW 523. (230 Nm). This means 2004 BMW 645 will have an easier job in driving up hills or pulling heavy equipment than 2006 BMW 523.
Compare all specifications:
| 2006 BMW 523 | 2004 BMW 645 | |
| Make | BMW | BMW |
| Model | 523 | 645 |
| Year Released | 2006 | 2004 |
| Body Type | Sedan | Coupe |
| Engine Position | Front | Front |
| Engine Size | 2497 cc | 4392 cc |
| Engine Cylinders | 6 cylinders | 8 cylinders |
| Engine Type | in-line | V |
| Valves per Cylinder | 4 valves | 4 valves |
| Horse Power | 175 HP | 322 HP |
| Engine RPM | 5800 RPM | 7400 RPM |
| Torque | 230 Nm | 447 Nm |
| Engine Bore Size | 78.8 mm | 92 mm |
| Engine Stroke Size | 82 mm | 83 mm |
| Engine Compression Ratio | 11.0:1 | 10.5:1 |
| Drive Type | Rear | Rear |
| Number of Seats | 5 seats | 4 seats |
| Number of Doors | 4 doors | 2 doors |
| Vehicle Weight | 1632 kg | 1715 kg |
| Vehicle Length | 4850 mm | 4840 mm |
| Vehicle Width | 1850 mm | 1860 mm |
| Vehicle Height | 1470 mm | 1380 mm |
| Wheelbase Size | 2890 mm | 2790 mm |
| Fuel Consumption Overall | 10.9 L/100km | 11.8 L/100km |
| Fuel Tank Capacity | 70 L | 70 L |
