+1 for ATP as well
DK...most of the time it is done on stock turbos as it replaces the ceramic wheel with a steel item and allows you to run more boost safely. With my old gtst I went from 145rwkw to a safe 210rwkw but then I added other items as well. As for anything else that might need to be changed, it will depend on how much power you want...for my 200+ I added FMI, computer, ported exhaust manifold, fuel pump and reg, air filter and exhaust.