i think its a resonator( it is/was on all of my mn12's so far), you /shouldnt/ have any problems, but they may get onto you about noise. you pull that resonator off and it gets fairly loud fairly fast, and it will drone a good bit around the 1800~2400 mark so you had better get some good mufflers to remedy that
Are u talking about removing the 3rd cat or resonator or both?? If you remove both you should still pass but it all depends on your states test ect.. I have duals with stock cats and i pass fine. Youll get somewhat louder with those 2 things off if you just take the resonator off it will be a little louder not much.
Both I guess, I will be completely honest and say I dont know what or where the resonator is. I konw there is two cats by the manifolds and then the "Y" pipe to another cat. My plan is to replace the Y with two pipes and muffs.
the resenator looks like a little muffler..about a foot from the third cat,,,if you remove it it will drone as i did it and also no mufflers..am going to put a center in.. center out.. flowmaster race muffler in place of the resenator ,, almost the same size as the resenator
I thought about side pipes for a while, and yes it is possible but its not a good idea. You will probably scrape alot. I think there is somebody on here that used to have side pipes but the pipes kept getting ripped off so he ditched them.
My V-6 has 3 cats, and it had a resonator, too. The resonator is gone. If I ever find some 2.5" downtubes that I can put on 2 high flow cats only, then I'll go 2.5" out to the mufflers. I'll have to add one muffler as I only have one now.
The Parts Bin Special is DEAD! It is being parted out.