I didnt know the parts were cheaper also. And one thing, please don't call nitrous, nos. Unless u r talking about a Nitrous Oxide System, then you can say N.O.S. Please dont be like Fast and the Furious. The Original Suspension allows for stiffer spring rates than the manufacturer Full Customize Suspension. The Stage 5 Turbos have almost the same power output as the Stage 4 (or for smaller displacement engines, only stage 2 or 3 are the highest output turbos available), more or less. Also, the Stage 5's also dont lag as much as the stage 3 or 4, even though lag is not much of a problem in GT4, with the exception of the Option Stream Z (below 3500 rpm, it lags like no other)