This may be a stupid question, but a lot of people say the '06 WRX up pipe has no cat, therefore it's unnecessary to mod it unless you're getting a bigger turbo. However, I consulted the service manual (downloaded from techinfo.subaru.com) and it says this:

The pre catalytic converter is incorporated in the turbocharger joint pipe (up pipe), the front catalytic converter is incorporated in the center exhaust pipe (down pipe), and the rear catalytic converter is incorporated in the rear exhaust pipe.

Is it wrong? What gives? Thanks for your help!

 

To my knowledge there is no cat in the up-pipe on MY06+ 2.5L

 

you are right sir. no pre-cat in the 06+ WRX's and the STi never had them.

 

Just got off the phone with a tech guy at Cobb. You guys are right - there's no pre cat for '06, meaning not much performance gain for swapping it out. Apparently they haven't posted a new version of the service manual on the Subaru site, so anything you download is actually for '02-'05. Not surprising I guess - I already found out the hard way that the manual's not always right when I over-torqued one of the bolts on the jack plate and broke it off!