How many cats does the WRX come stock with ? 3 or 4? I'm looking at replacing the factory up-pipe and down pipe, but did not know if these replace ALL the cats or if the main large cat under the car will remain after these mods. Who also makes the best CEL eliminator ?? Thanks! Mike

 

The WRX has 3 cats, one in the uppipe, downpipe and one in the midpipe. There are a few cel eliminators out there, Scoobysport- www.rallyperformance.com , www.vividracing.com sells a ILP cel fix also.

Matt

 

You might want to look into an exhaust with a removable third cat (replaceable with a straight pipe). This will help with emissions/inspections without having to put your factory unit back on. TurboXS sells such a beast for its TBE. Any of the CEL fixes should work fine, the concept is pretty straight foreward.

 

Thanks for the info guys. Do some downpipes referred to as cat-less downpipes remove the mid pipe cat as well, or just the second cat on the downpipe only ?? Tks, Mike

 

The first cat is on the up-pipe, the second on the downpipe, and the third in the mid-pipe. Most catless DPs only remove the second one only - although most people buy the DP and the midpipe together.

 

A catback exhaust is a fancy way of saying muffler. No cats replaced.

 

Good question. Now the the WRX is over a year old we should have some people who have been emissions tested. How many cats have people passed with? There's no way you'll pass with 0, but how about 1 or 2 or 1 and a highflow or just a highflow?