whats wrong with what you have? go for 400 400 on the turbo you have, nice and responsive and doent run out of puf to fast, it seems to me that al thing s are a compromise with the yb and you will not always get the response of a t3 with the legs of a gt35 lol also although i agree that smallest turbo to get to the aim will give best response it may also cost most when you get bored i.e. upgrading all the time, if your loaded this is fine if your me this is not lol