Rear O2s get mounted after the hi-flow cats.

 

take it to an exhaust shop. Tell them that you want to replace your 4 oem cats with 2 high flows and you don't want any CEL's on. They'll fix you right up.

 

When I ordered my two mag's I also ordered two "quick fit" pipes for O2 sensors. There were just 6 inch long pieces of 2.5" pipes with bungs for the O2's welded in already. They were only $5 a piece, and sure made the guy at the exhaust shop's life easier. Get up under your truck and see if you think welding and cutting where our cats are at looks like fun.

Think it definitely saved some time on the install too!

 

Had the 94106 on my old setup. very loud when used with super 44's and X pipe. check sig for video. amazon has them for $65 each

 

alright. but, what about high flow cats and no muffler? what kind of sound would that make? im sure it would be loud but idk what kind of tone it would have.