If I understand it correctly, the Works exhaust (DP+IP+AB) does not
include a high flow cat. If so, do most folks run with the stock
cat? How restrictive is the stock cat with this setup? Has it been
quantified, ie. in hp loss when comparing to high flow cat?

Also, for those running a high-flow cat, do most high-flow cats
pass CA emissions?

Thanks,

Joe

 

Many of our customers run the stock cat for environmental reasons and don't want to be bothered by Check Engine Lights, dealers, or local authorities.
Now how restrictive is the stock cat? Well that depends on your level of modifications. Actually the stock cat is quite a decent piece. It flows quite well and is constructed like a tank. But the more power you are making, the more restrictive it becomes.
That is why we are offering a high-flow cat in our WORKS Racing program very soon. We have not quantified all of the numbers yet but our new cat is designed to run clean without sacrificing any flow.
Do other cats pass CA emissions? We have seen many many EVO aftermarket cats and if there was a solid, reliable one out there, then we wouldn't bother making our own.