I was looking at this turbo on ebay ,and i want to knopw if its a good deal.(for my 90 GS)Also will i need any other additional parts?
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7933572560&category=33742

Couple things that stand out for me.

No mention of what compressor wheel is in the turbo, that I could see. Hard to make any guesses about performance.

The to4e/b housings dont come with a 2.5" outlet, its 2". The To4S has a 4" inlet and 2.5" outlet.

SS manifolds are not less prone to cracking than cast, they are more likely to crack. Not that they all do though. I've had good luck with my SFP manifold so far.

I think that was it. If this phsyically bolts to the head thats a good start. But there is still more work to do to turbo a NT car, and I'm sure its in the sticky at the top of the topics page.

will that bolt on to a GS¿

it wont bolt on to a 2g gs but it will bolt on to a 1g. the 1g nt is just a nt version of the 4g63

ok ,thanks for the info. I dont want to go and make a mistake and buy somthing i dont need.