First things first: the Code3 is the slowest of the pullies available. It is very close to the ASP 178, but as you probably noticed from DragTimes.com, the top runners there are mostly ASP 178s.

The 181 and larger pullies provide a higher rate of spin for the supercharger. But more spin does not always equal more power. It can also lead to more heat, which robs you of that power. I'm not saying that the bigger pullies don't work. I'm just saying that you need to be prepared to do more mods to deal with the added heat and air. Also, with the bigger pullies, you're running even harder up against the limitations of the the intake manifolds. The stock manifolds will only flow so much air. So a bigger pully without additional mods won't get you much satisfaction.

There is one distinct advantage to the Code3, and it doesn't have anything to do with performance. It is _really_ easy to go back to stock when and if you ever need to do it.

As for the tuners, I haven't been real impressed with either one. I've heard people swear by both. You're essentially going to have to pick one and live with it as Doc says. If one is geographically close to you, go with that one. That way you can pop over to their shop whenever you need a retune or whatever.