Originally Posted by 2gr84u

Well the LS motor will have more power boosted then just a GSR swap will have, and a boosted LS with the auto to manual swap can be done for as much if not only a little bit more then the GSR swap.
Its gonna be tough to choose with the exhaust you run right now. If you Know for a fact that you will be bolting up turbo by the end of the summer then you should go head and get the 3in and deal with the potential powerloss untill your boosted. If its gonna be a while before you go boost then you should get the 2.5 and be set for normal driving and be pretty well off for boost.

Your forgetting a good hunk of change here that i my self have found out to be a very importent part of being boosted. Your gonna need a clutch, the stock clutch does NOT hold up to boost lol so keep that in mind