mods I have are

HKS Hiper cat back
Helix downpipe
Helix up-pipe
K&N panel filter
silencer removed

I have an 03 wrx and have a chance to buy an invidia header for pretty cheap and was wondering would it be worth the $500 (installed with manifold swap)? I've heard of 30HP gains, but if the header doesnt add that much power with a stock turbo then I'll spend my cash on a cobb ECU flash. any real world numbers would be great, also with all my cats gone noise would be a factor...how obnoxious would it be? (I live in So. Cal) Thanks in advance.

 

oh I forgot, does this header include an uppipe aswell, because I just bought the helix uppipe.

 

So far, no aftermarket headers make more power than stock.

 

thanks Ban...looks like cobb tuning should be the next step. why do headers cost so much then if they dont free up any extra HP?