[wfbal]

I agree with Deathpunk,
because of it smoothe M20 engine, the E30 325i/is is a FAR better *street* car than an E30 M3. And it can be as fast as a stock E30 m3 with the correct minor mods.
It is very easy to replicate the M3 suspension (same weight, same chassis) and a 4:10 diff will cancel the straight line accelaration advantage of the M3 (on the street).

On the track it is a different story, the m3 will always be more balanced (a little less weight in front), has more clearance for big tires and if you can keep the rev very high, does produce more power.

I agree that the e30's are better balanced than 911's, but the steering feel on my SC is way better than my 325i's.