what is the real difference in the 4" vs the 5" TBE? i dont have any other mods as of right now. but i am planing on doing intake, exhaust, and some sorta downloader. i am not sure as to which one yet. i have heard that the XRT is good as well as the SMARTY. but i like the way the edge juice w/ attitude has the monitor to display the boost, egt, and whatever else. so what do you guys suggest?