Ok, I have a 2006 GT that is stock except for the exhaust. I'm not sure what exhaust it has, but it was changed by the first owner. So now I don't know one S/C from the next. I looked at the Roush M90 because Roush and Ford work together. Make sense...I don't know. I keep reading that the stock motor is good up to 425 horse power, the M90 is 435, close enough I guess. If I were to put in the S/C, what other parts of the car would have to be changed to support the horsepower? And is the Roush a good S/C or is there a more inexpensive one that's just as good or better? Thanks FYI......I know how to drive and pump gas.....that's it.