How is it fitted at the front cos a 3/ 1/2 wont bolt up it needs a reducer pipe. Only one company I connected could actually produce a 3 1/2 system & even they had to buy the bends in. Biggest Mongoose is a 3" can i suggest you are measuring the tail pipe, which on mine is 4" the rest is 3".
Ye the tail pipe mofo's. Not sure on the diameter of the actual system but it dont look muchg smaller than the tailpipe. It will most likely be 3" system with 3 1/2" tailpipe
