Bottom line:
Going to a bigger TB on the near stock 2.5L is a waste of money. Optimize the one you have.
IMO a 75mm MAF is a waste too since your not even going to outflow the one you have. Its good for about 300 hp. Yes, the Pro M would probably flow better, but I would say the hp gains are minimal.
Btw, there is a thread stickied at the top of this branch, discussing this very issue since its been discussed so much.
