Careful when you start talking about modifying stock exhaust.... Some people have opinions about that, and they have nothing better to do but post them along with charts and write-ups.
I bought a aftermarket and posted about it, then it turned into a 6 page debacle.
Apparently they have been banned in Communist California.
I wish you the best of luck with your endeavor.. And hope the tree huggers don't slam you on your post, because apparently since I bought my pipe I have ruined motorcycling for everyone for ever and ever.
But to answer your question, get an aftermarket pipe. That way if the California Commies do get them banned you can go back to stock.
Sent from my iPhone using MO Free