hey Mike, welcome to the GTOForum!
I am assuming since you quoted 17% that your an auto. Correct me if I am wrong.
check out Tom's site,
www.tbyrne.com and you will see there are a plethora of options available to ya. magnuson has an 05 kit, as does ProCharger, Vortech, and even STS turbo has a kit.
As for the gains, adding another 150hp is roughly a second so you can expect to go from a 13.0 car to a predicted 11.9, which aint a bad deal!