In Reply to: will an 18mm spacer work for 17" e36 m3 wheel posted by Scott325i on April 18, 2002 at 10:48:47:
The 17x8 BBS fitment for the E30 M3 is a 38mm offset with 18mm spacers, giving you a 20mm offset. These 17x8ET38 wheels are for E36s, among other things.
If it's a 7.5" or 8" wide E36 wheel, I'd say you can't go wrong. If it's an 8.5" wheel, you'll probably want to check the offset to make sure. If they are staggered, i.e. 8.5" wide only in the rear, you'll be OK as well.
I assume you have a set of BBS spacers? Most people just go with H&R 15mm but 18mm should work fine too.