1080p: Audi R8 4,2 vs MTM Audi RS6 730 HP
http://www.m5board.com/vbulletin/e60-m5-e61-m5-touring-discussion/141437-supercar-shootout-august-2009-koenigsegg-ccr-evolution-nissan-gtr-bmw-m5-porsche-carrera-gt-ferrari-599-gtb-f1-porsche-911-gt2-997-lamborghini-lp560-4-gallardo-jaguar-xfr-more.html HD: Audi R8 4,2 vs MTM Audi RS6 730 HP
B5 RS4 with C5 RS6 V8 engine
Courtesy of rs-quattro.de these pictures and video highlight an awesome project of transplanting a C5 RS6 V8 engine into a B5 RS4 body.
Audi A8 W12 6.0 Top Speed 295km/h
This is a software upgraded W12 12 cylinder 6.0 liter (366Cubic inches) engine at around 500hp. The run was done on a professionally monitored speedway. The speedometer went beyond the marked area, but would most definitely show about 320km/h. You can compare the speedometer numbers with the GPS numbers - the GPS is precise. The max speed should be around 300km/h (188mp/h)on high octane gas, this run was done on regular gas.