It could make you 40hp, it could make you 100hp, IT ALL DEPENDS ON THE SIZE OF THE TURBO. What turbo are you looking into getting, lets start there. It also depends on if your gonna be running 6lb of intercooled air, or 6psi of non intercooled air. Your gonna get different hp off the same turbo even if you intercool it. There are so many variables in a turbo set up, and so many different turbo kits that your gonna get different results more times than none. http://www.importreview.com/d_turbo.html look at that site there is a few dyno charts with hp for several GSR's running low amounts of boost. I understand yours is just the LS, but maybe that will help.