I admit it, I'm a bit confused on the pipe diameter measurements of the Stillen G35 exhaust.

I've searched and read till my eyes crossed and haven't really found a answer to my questions.

Is the advertised size of 60mm the inside diameter or the outside measurement of the exhaust pipe? How is the fit to a set Kenetix HFC that has a inside diameter of 60mm? It looks close on paper but how does it fit in the real world?

What is the Stillen exhaust made of? 304 stainless or something else?

Thanks for the help!