How much hp do you think a catback exhaust and an intake will yield? State what combo you have and what hp gains you think or know you have gotten. I have the Injen intake with an RMM exhaust. I have no idea how much hp I have gained.

 

I think I probably gained around 15WHP (about 22hp) with my Borla exhaust and K & N FIPK. Pretty typical gains from any exhaust/intake combo. Now, modify the intake (re-route to only take in cold air) and throw an SAFC II and there is going to be a tremedous effect on HP. Doing these items can add an additional 15-20WHP if done and tuned properly!

 

Put it on the dyno and find out for sure!

 

Any idea what the gains would be for an '03 GS300? I'm debating which to do first....catback exhaust(ie, Magnaflow or Borla) or an SRT/ECU type upgrade?

 

Little bolt-ons are not going to give you substantial gains unless you do every one known to man. If you are looking for a decent upgrade you should start looking into forced induction or nitrous.

 

Yea I definitely plan on going the FI route in the future, but I just wanted to know about how much hp you can get from this combo. What kind of power is the GS3 putting to the wheels in stock form?