This comment is not for the OP who already knows what he is going to do..... From the first post.
Any vehicle specific forum you go to, invariably has a performance section. The speed freaks hang out there. While they have a wealth of info, they also share a common theme. There are ALWAYS many posts of people trying to solve issues with their custom tunes.
Amazingly, none of them seem deterred one bit by the problems... They seem to relish in them.
So for those that may be reading this, and are thinking it is all roses.... Look twice before leaping.
It takes a special kind of person that is willing to overlook some downsides so they can get more performance.
The original manufacturer has an engineering dept. that dwarfs all of the speed companies put together... If they "left some performance out"... There is most assuradly a reason.