I'm building a custom based on a Yamaha XS650 and am considering using the Supertrapp Universal Slip-on Megaphones. The model I'm looking at is 1425-17500. I can't tell from the online catalogue how long they are? Can you help? I also can't tell if there is any provision for mounting brackets? If there are none can I TIG weld mounts directly to the stainless outer shell?
I'm making 1 3/4 head pipes from J bends so that part should be OK.

THANKS
Don