Way old thread here, but this is relevant to my interests as I'm picking up a ZHP soon, had a bunch of E30s, and autocrossed them pretty regularly.
For a true "only car" (DD + autoX), the E46 seems so much better. If you have a true daily, I think the E30 is a better 2nd car. I *love* E30s, but they are no longer the cheap option they once were.