Anyone have any idea what kind of HP gains I can get with these MOD's on my 02 WRX.
Plus will any of these MOD's give me more boost or quicker spooling because the engine is breathing better?

Prodrive axle back muffler, up-pipe and K+N filter

Thanks

GM

 

Ditto on the K&N

Uppipe = 8hp
Axle back = 8hp
K&N = 0hp

Total = 16ish hp

 

How much more gain you you guys think he'd see if he went with a DP-back, including removal of the 3rd cat, instead of just an axle-back. A few more feet of striaght pipe can't cost that much extra.

 

I'm guessing here:
Axle-back = 8hp
cat-back = 10hp
dp-back = 15hp
turbo-back = 25hp

Note: Not all catbacks are created equal. This example of 12 catbacks show that increased horsepower can vary as much a 7hp. HKS scored the highest with 11.1 hp more and M2 scored the lowest with 4.1 hp more peak. On a side note M2 is the most expensive of the bunch but the quietest.

12 cat-backs compared:
http://www.mattrandolph.com/wrx/cat-...omparisons.htm

 

You really need both. But I believe the uppipe would show a little more gain with quicker turbo spool up.