I do know the GSR intake manifold wont fit on a SI,CTR, or ITR head. But the TB's have the same bolt pattern. If your gonna spend the $$ to get the GSR TB why not just get an ITR/CTR, Edlebrock, Venom, etc. What other mods do you have done to your car, cause if you dont have all that much done, its not really gonna make that big of a diff. to put a huge TB on it.