Im running a 3' pipe with magnaflow res, and dual apexi n1 turbo exhaust, i left the cat thinking i'll pop up my engine light up... i really want to delete it. if so no oxygen sensors will pup up. i dont really know about that... any could help its a 04' TL at

 

we have RV6 pre cat deletes and test pipe that will not cause a check engine light. I would know because I have them, along with many other members. Search in the performance and parts mod section....

 

I have magnaflow with the 3rd cat delete and I am thinking of getting universal mufflers. I don't think you will have a problem, my friend had the same setup with apex ws exhaust and it ran fine.