I plan to soon begin mods for my '07 WRX wagon, but even after reading the FAQs and other helpful threads around here, I still have some questions. Hopefully some of you can help me out. Initially, I'm going to get a Cobb AP. From what I have read, the AP can give you up to 25% more power output. A stock '07 WRX is listed at 227hp, so a 25% increase will give me something in the range of 50+ more hp. So to me it seems as if the best bang for the buck right out of the gates is the AP. Book it.
After that, I will be getting a downpipe. If what I have read is correct, the best DP for me would be a bellmouth/divorced catted DP.
From here I get a little fuzzy. What kind of power gains are typical w/ a downpipe modification, if any?
Titanium tipped mufflers and the like all appear to be mods for the sake of a particular sound, or the grown-up equivalent of sticking a baseball card in the spokes. Is this accurate?
Do any mods to the exhaust system besides the downpipe result in a power increase?
Speaking of sounds, since I bought my WRX last August, I have never once actually heard the turbo spool. I'm pretty sure it's working since the car is quick, but I have no current way of knowing. Is this typical of a stock (2007) WRX?
What other modifications would give me more power at the wheels?