The wastegate is the gadget on the side of the turbo that controls boost. It opens up to bypass exhaust around the turbo when boost reaches the desired level. Well, it SHOULD do that. The three inch downpipe is probably more than you need, unless you have lots of other mods on the car. I got the "stock replacement" from ATR, which is the DP-101. It has better flow than stock, and less clearance problems than the bigger pipes. If you got with the external wastegate then you have to buy the wastegate, which is another $300!! Not needed, not until you get REAL fast!! If you port the turbo, that will probably do more to help than the three inch pipe, and it won't cost you anything but time!