They have a Solstice GXP. Turbo Ecotec, 260hp, 260ft-lb toruque. Run a double turbo with the stock GM turbo as the low end and then put a larger turbo to take the boost higher and you'd have a faster more efficent car for less.

i have my name on the list for a base solstice. its 18 grand for the engine and installation only. they are jus under 20 grand us, and about 25 grand canadian for the base model. im gunna go the turbo route as opposed to the 18 g vette swap but damn 400hp to the rear wheels on a lil pontiac roadster has gotta be fun and prolly dangerous.

^^^^ Pontiac GXP should drop sometime this summer. There's your turbo.