Thats what I used on the 550, it really works, the steel does seem thicker. I was still able to dent it up good though. ID KX500 I'd think you could get it & just reflange as it's a cr500 low pipe which most af build pipes are based off of. I had to persuade the stinger tip to get the angle I wanted, just used a fence post pipe set in cement to get it were I needed it.
The - is the welds look a bit bird s**t for the cost & pilot jetting with it really seemed screwy.
Did you experience any jetting issues don46 ?