amgalex

Had an x pipe mod done a month or so ago on my 2000 e55
sound was just a touch louder with this mod, honestly not enough to be noticed so I decided to put high flow secondary cats. Purchased two on ebay and after receiving them and finding out that lots of cells on the honeycomb are clogged throughout the cats I decided to just remove the cats and replace with pipe.
It was not easy finding a shop here that would do it. After going through every exhaust shop in town I finally found a shady one that did it for me for $200 and let me keep the cats ( should be able to get my $200 back when i sell them)
Sound improvement is noticeable, I would say got 20% louder compared to just a xpipe mod, but it is still not that loud so Id say you can safely remove secondarily cats completely and not have to worry about the car sounding like a dragster.
As far as performance I can not tell any difference honestly but it is hotter and more humid outside so who knows, so far 1/4mi times and trap speed are identical to my best 2 month ago in colder weather.

mysticblu999

Did you have the o2 sensors welded back in or did you use a o2 simulator to stop the check engine light from coming on?

MR888

Secondary cats don't have O2 sensors?

amgalex

yep

so never will you have a CE light from this mod.

mysticblu999

I could never check, my car is way to low, sometimes when I walk up to it my foot gets stuck in between the car and the ground!