Hey, my friend is looking into getting a new pipe for his 2001 gsf 1200.... right now he has the stock header, and is lookin into gettin a slip on, but he wants to know whats the big diff between a stock and aftermarket header...
is the aftermarket one wider? as it it lets more air pass through?
is there going to be a big diff of sound and hp if he take a slip on vs a full sys?
is the full sys worth the $$?