There are a bunch of guys over a Bimmerforums that have done it. Just drill down to the E36 part of the forum and do a search for Bumper Lip. You will see a bunch of threads about Non-M bumper lips.
I saw a Hellrot 328i 4 Door with the standard bumper, but a M3 lip on the bottom. From what I have read the middle fits fine. The issue comes at the edges. I figure if I can come up with a procedure (tape and scribe?) or some type of template then eveyone can have a cool bumper lip for cheap. DDM sells em for about $50. All you need are some stainless self taping screws, stainless washers, and some 3M tape.
Cheers!
~Mike R~
The Ti is coming along nicely TiFreak! I think if you get the right set of wheels, the whole thing will come together. Check out
www.wheelsandcaps.com They have a ton of BMW replicas and the current special is free shipping with any set.