took a page of posts just to figure out what was going on... be clear people!
If the only reason you're converting to 5-lug is for a wider selection of wheels, it's probably not worth it.
To convert, you basically need the suspension and brakes from a 5-lug car [E30 M3] and put them in your car.
Here's a parts list from http://www.davelength.net/car/5lug.html
Front strut tubes
Front brakes (calipers, rotors, backing plates)
Rear brakes (calipers, rotors, backing plates)
Front and rear sway bars and swing supports
Aluminum control arms with offset control arm bushings
As far as I know, there aren't any conversion kits available.
Have you checked out tirerack.com? They have like 25 wheels available for the e30. I've also heard that you can use Volkswagen 4-bolt wheels, but you need some spacers or something like that.
As a note - I've never heard any good things about TSW wheels.