A chip would be a good investment. A 5 lug swap tends to be expensive, you can you the front strut assemblies from an e36 and some trailing arm 5 lugs with hubs etc I think what the z3 has works. Its not going to be cheap but you can't just swap a hub because it won't fit, not even the e30 m3 stuff unless you get a complete set.
Here is a link to a place where you can buy all the needed parts: Treehouse Racing - 5 Lug Kit
You might be better off to try and buy them from someone parting out a car or a shop to save some money but do your research and make sure you get the right parts.