Not really if its fully modded and on racing softs.
I often race online on a server that have 1 lap nordschleife races with fully modified DTM and GT500 cars. Fully modded CLK, which I think is the fastest of the DTM cars around NBR, can do sub 6.10 time from a standing start.
The fastest <680hp, >1000kg car I have tried though is the Nissan Fairlady Z LM racecar you win from 1000km Suzuka B-spec race. Yesterday I did a 6.02.7 in a race from a standing start. It was with SRF though but add a few secs to the time and its still fast.