Alan B. - With such a short rear overhang on your design. How will you be routing the exhaust? Do you have a brand selected for the muffler? Are you required to run a cat.?

I am running the stock manifold out the back just like stock and then looping sideways behind the Watts link and stacking the cat and muffler .

I am seeing a guy this afternoon about a Yamaha R1 stock exhaust can (muffler). The inlet size is 2.4" (or 60.5mm - Dominic!) . I am thinking that this setup will sound particularly and agressively good on the 4AGE.

Steve, I'm not completely sure yet what I'm doing.

I'm making a manifold and welding on a boss for the Oxygen sensor, then probably keeping the cat.

I too have a bike can...just not sure about it's mounting or of the pipework between it and the cat.....