I have an 01 screw with all 4 stock cats with the o2s mounted INSIDE the cat not on the pipe outside. I was planning on getting the 94316 high flows with the mount in the cat too. But I went to a shop and they quoted 400 a side to replace all cats with the two high flows. There is no way that it should cost that much to chop and weld. I've been reading people saying 25-75 a side so I was wondering what you guys have been paying.

I have a gryphon I know I don't have to keep the rear o2 sensors but I would still like for them to be in. Also I was wondering if I kept the pre cats and replaced the rears with the high flows, if that would sound as good?

 

All or nothing, just the rears will barely be louder. Just find a new shop. It was $250 for me and I brought the cats. Price depends on area