Fantastic info Jim! Great work! I too recall seeing these comparison pics somewhere. Its quite obvious. But then again, as it seemed all the European factory teams were cheating in some form, the consensus appears to be that this all evened itself out, so nobody bothered protesting. I do recall the first six M3s were all disqualified at Monza for Round 1 of the WTCC, so this obviously wasn't always the case.

Incidentally, I remembered the Rouse RS500 at the '87 Bathurst as being quite distinctive in that the front sat much lower than the other Sierras. The car was also on more of a rake. It looked fantastic.