For reference the M3 either placed 2nd or 3rd the year it was there. It was a none comp package car and it ran a 1:42:9.
The Boss that ran was a Laguna Seca (where they did the finalized suspension tuning) with an X brace for rear seats and was in the 41 area. Laguna also rewards power.
M3 340/260 rwhp/tq
The problem with the 1M is the power falls on it's face past 6000rpm and it's also nowhere near as responsive as an M3. Also, the 1M has a high roof line so the weight is higher then it needs to be for it's size.