Just bought a 04 WRX sports wagon last week and I'm in the process of upgrading my exhaust, up pipe, down pipe and cai...Some peeps say that I may risk running lean with this set up. Do I need to upgrade my ecu as well and retune?

I don't plan on runing this car in the track. It's simply a daily driver, although I know that this car will be pushed and driven hard at times...maybe occasional autoX.

 

Yes, you will need a retune. Lean condition is not as much of a reason behiond it as making more power with a proper tune.

 

alex dont forget about the 04 open loop delay..loanpro you can do a search on that but its basically boost without proper fueling..and like alex said you will have way more power sooner if you tune.

 

Thanks...I can't wait Been a Honda guy for many years and I'm quite a noob w/subaru. Thanks for your responses.