Aye.. I have an M10 in my garage from my first car and I hated it. With the right gearing, it could get out of it's own way, but barely. And even if you do a motor swap, the M10 is worth nothing (unless you have a 2002 and are going for stock... and even then...).
I'm gonna say the same thing a fellow e30 owner said to me after I bought my 318i and that's to buy a fairly clean 325is and go from there. You'll save so much money.