I personally wouldnt stretch my bike, but i know the benefits.
More than a few times i saw faster bikes getting beat by slower ones all because the "slower" ones were stretched and got the launch on them.
It must be fun beat some 1k on a lil 600.
I actually like the arm, i hate extensions, a after market arm just look "righter"
i have a soft spot for stretched bikes, my 1st bike was a 93 cbr 900rr that was 8" over and i miss it... but just noticing, your swingarm lacks any lower bracing. for such a long stretch id be worried about flex under load, just my thinking though, but welcome! fcuk the haters, if you like it roll with it!