Ok so I recently upgraded to an 08 A4 2.0T FWD Tiptronic with 9K on it and I was thinking about upgrading some features. I know that some people on here think that it is lame to upgrade a FWD Tiptronic but I would like to squeeze out a little more HP from the car. Im new to tuning vehicles but here's what I had in mind so far.

1. Cat back exhaust probably Magnaflow
2. Cold air intake
3. Chip turbo
4. upgrade Diverter Valve and Fuel Pump

My car is still under warranty for another 3 years so I was thinking of either holding off on chipping the turbo or going with Stasis since it wont void the warranty. Are the other tuning companies like APR, GIAC, Revo, AWE reliable? Im not looking to race my car all over the place I just want to have the extra HP if I need it.

Does anyone know how much HP an exhaust and cold air intake will give me? Would it be worth it for my vehicle considering its a FWD Tip?

For the exhaust I am looking for something that focuses more on performance versus being loud, and I dont want it to drone.

Sorry if my post is all over the place I had a lot of questions and I wanted to put them all in one post instead of making 3 or 4 posts right away. Oh and Yes I already searched the forums and Google but couldnt find any definite answers to my questions. The Audizine post about basic upgrades was pretty helpful but I still felt that my questions were unanswered.