more to a race than just being fast... cornering speeds of DTM cars are way higher than JGTC, although that could be due to the track layouts, japan tends to have lots of long straights with tight corners.
Well Chrysler wanted to enter the 300C Touring Car into V8's but was refused. hehe, didn't stop them from becoming the pace cars though... good marketing ploy... "you won't allow us to race, fine, we'll lead."