street legal extra pipe differences?

[nambo-trev]

does anyone out there know if the extra pipe that comes with the nambotin replica has different internals inside like a cat or is it just the small extra stem coming off the pipe the only difference? i just want to know because if the pipe is the same with just a cat inside ill cut it open rip it out and re-weld it for a spare pipe. any help would be appreciated

[iancp5]

I "think", i.e. not certain, that the ones with the little stem are catalyst pipes. You'll know if you've ever run it. Well down on power. Also heavier than normal.