I found a decent site that offers rebuild/new performance parts for Series I to include full heads, transmissions, radiators, body parts and entire engines. Not really a piece by piece performance shop but if you have the $ to spend it might be worth it. I haven't bought anything from them yet so I don't know how well the customer service is but they offer a warranty for almost everything including 70,000mi on a rebuilt engine. Check it out:

http://www.pontiacautopartx.com/


Jason