What turbo would be good for my stock Grand prix gt 3.8 naturally aspirated engine ???

use a turbonetics 62-1...perfect turbo for our 3.8L.

Here is a kit zzp makes they also have a base kit thats a little bit cheaper...
http://www.zzperformance.com/grand_prix/products1.php?id=411

Base kit - http://www.zzperformance.com/grand_prix/products1.php?id=410