The first couple of years I've owned the car I just drove it. Didn't really touch anything. Then I came across a e21 Recaro driver side seat on craigslist for $40. It was trashed but for $40! The guy I bought it from turned out to be a super nice dude who's become a friend. Watch out for Austens Superchaged M3 swapped e30.
I spent the next year lazily on the lookout for a passenger seat at a decent price and eventually one popped up on ebay. Price was reasonable so now I had the set.