This has nothing to do with power adders, moving to v6 tech.........
First thing I will say is get a tune from a company that only deals with tuning. Checkout this Tuner/Cold air intake combo from VMPtuning.com
http://www.vmptuning.com/store/index...=198&parent=92
This is the single best mod combo you can do on a 05+ car.
The tuner stores the stock tune before it upload the performance tunes, so should you need to you can put the stock tune back on before it goes to the dealer etc...
You will get a nice solid gain of around 10-12rwhp with the tuner/cai combo. Its a proven package that works. We have a few members here who have that combo and love it.