Compression is going to make power, it's going to spool you faster and the rods are the same to my info. Not to mention driving around town on the L26 is much better

L26 is in base model Grand prix's some buicks ummm .. any N/A 3800 after 2004 for pontiac and 2005 for all GM. Stock L26 is cheap and if you do happen to blow it it's cheap to repair. If anything happens you're going to chip a piston and that's not a hard fix either really.
Any good Intercooler set up is going to cost you over $1000, the reason it's 2.5" piping is because you can't fit two 3" pipes through the fender. It's an easy fix though, angle the turbo toward the passenger side, and run piping to the IC from there. I don't believe in that sheet metal intake I like the L26 one, or using an Aussie style set up. But that would solve a lot of your problems and make running the 3" piping much easier. Maybe on the Stattama kit it is upgraded, but I doubt it.
That's an XP cam, Cartuning Turbo kit w/ 3" downpipe, L26, Canadian Cylinder head techs heads and LIM on alky and Sunuco 94. I BELIEVE that was on 19 PSI it was either on 19psi or 21psi. But either way that's a lot of power on pump gas with an XP, which is not a great cam for turbo set ups !!!
The Stock rims are good, but there just aren't a good array of tires in that size anymore IMO.
But really, talk to Matt M. He'll help you out, he was pretty damn honest to me when I talked to him about a build last time.