ok, so here is the problem with the exhaust that I've heard TWO people say:
the long, straight pipe that goes from the axle to the header is too short to bolt right up to it.... so you either cut it short and add a cat/presilencer, or add an extension if you want it to bolt straight to the header flange.
Also, that is WAY overpriced on the wesite. you can get one of those for $200 plus shipping on ebay.
As far as the cat, bonez are ok, but if you only need it to be temp, here's a cheap alternative:
http://cgi.ebay.com/ebaymotors/1988-...Q5fAccessories
If you have a header:
http://cgi.ebay.com/ebaymotors/CATAL...Q5fAccessories
EDIT: I was actually going to buy that system myself, but with some poking around, I managed to find a mint condition HKS Silent Hi-Power for 375 shipped! I'm sure if you look around no-pistons, evilforum, and ebay enough, you will find a great deal on exhaust components.
EDIT #2: got my RB header for 150 shipped from some guy as well.