20v or a AE101 GZE best bet. GZE is pretty straight forward not too much, still got boost, and if you decide to go bigger everything is already good for boost. You are going to put too much money into a turbo 4AGE cause nearly everything needs to be changed and @ 7pnds (I would never run more on a stock bottom end) you will prolly only make the same HP a 20v makes and have more money and a less efficent head.