Well it is GTM if it isn't in one of the twenty two packages just call and see what they can do
Edit: and yeah most of the t25 plus turbos are going to be huge, two 300 hp turbos is as much as the stock block should push, but running bigger turbos may work out better for traction, you know give the tires some time to catch up, and then down the road refresh the motor with new pistons rods and studs and turn up the boost controller.