German sport-auto 01/2003 has a comparison of the new Audi RS6 against BMW M 5 and AMG E55. The RS6-limo in standard trim 450 HP engine and 1909 kg empty weight was tested 0-100 km/h in 4.4 sec. and 0-200 in 15.7 sec !!

Last month the same magazine tested two tuned RS6 of which the top one by Sportec/CH with 500 HP only had 16.6 sec. for 0-200 km/h.
It seems that the Quattro GmbH (Audi-Sport) also adopted the more and more common approach to slightly "prepare" turbo charged cars for tests by car magazines. This limo surely had in access of 500 HP, just like the E 55 which would not have the below listed results with only 476 HP.

The RS6 won the test by 1 point (41), second came the M 5 (40) and third the E 55 (37). An excellent performance of the M 5 even though the car is slightly lighter in empty weight but it is on the market for 4 years now and its engine is not charged. The E 55 lost some points in handling.

Some more detailed test results:

category / RS 6 / M 5 / E 55
weight / 1909 / 1798 / 1944 kgs
engine / V8 TT / V 8 / V 8 comp
HP / 450 / 400 / 476
HP/kg / 4.2 / 4.5 / 4.1
0-100 / 4.4 / 5.0 / 4.6 sec.
0-200 / 15.7 / 17.1 / 14.6 sec.
max. speed for all 3: limited at 250 km/h
tracktime / 1,17.9 / 1,18.5 / 1,18.0 at Hockenheim