I've spent my share of time scouring the Internet for 944 Turbo S information and have found some good sites and contacts. The partial list below is included in case you might be interested in checking them out.

Vitesse Racing
Vitesse has just about perfected the DME/KLR chipset and are producing some of the most unique, effective performance modifications ever released for the 944 Turbo.

1988 944 Turbo S Silver Rose
Very comprehensive site includes registry, vehicle data, production info, and more. Doesn't seem to have been updated recently, but worth a look.

944 Turbo Chronicles
Lots of photos of one owner's trek down rebuild lane. Regularly updated site, chronicles the rise and fall of an '89 944 Turbo S from cherished track beast to someone else's problem... Lots of good info here even though it was sometimes painful to read.

924/944 FAQ
Good primer for those just starting the search for a car. Also has some good troubleshooting tips for the 944 owner.

Porsche 951 Engine Rebuild
Lots of photos of one owner's trek down rebuild lane. (Sound familar?) This poor guy bought a 951 that needed a new engine a few days later. I would have had quite a colorful verbal exchange with the used car lot but that's just me.

Lindsey Racing
Lindsey has some nice products. Well known for their Boost Enhancer, they have many other higher performance parts too. They're always willing to speak on the phone. Site has lots of good info, including some installation how-to's.

Speed Force Racing
I've been eyeballing their exhaust systems for some time and although my OE exhaust looks fine even after 13 years, I bought their stainless steel cat-back. It looks and runs great and was a good price. Later I'd buy their cat pipe and Stage I headers. Photos are in my Gallery.

Porsche 951 RacerX
Lots of good install/technical information and wheel/tire combinations are found here. Great photo-quality downloads of old Porsche ads, too.

Hendrick Porsche
If you have to go to the dealer for special parts (wastegate gaskets, new control arms, etc.), you need Hendrick Porsche. Fast shipping and at least 30% off retail (via mail order only) on REAL Porsche parts, these guys will bend over backwards to find a part number for a 20 cent washer. (No kidding.) Call the parts counter toll-free 1(800) 315-8193.

Zygmunt Motors
Ok, ok. I know their website is bimmerparts.com, but I SWEAR these guys are one of the best places for quality replacement parts for your Porsche (if you don't need a Porsche box). Lightning-fast shipping and good prices, they sell parts for all imports. They take PayPal, too.