Has been discussed here quite much, and use your head a bit too. 
If it has I have struggled to find it in clear unambiguous terms (much like the idea that a must for the ZX14 headers is to bend the mid-pipes

) - which is always the folly of motorcycle forums, everyone has an opinion

I don't think the bike is too off as a result of the mod, I have no surging at a steady throttle, there's no flat spots, and no backfiring beyond the typical AIS burble on decel. My 300k ride on Sunday saw as expected highway mileage and no noticeable increase in engine temps.
Anyway, FuelMotoUSA got back to me overnight and are of the opinion that "
vibration is an effect of mass in motion, generally speaking we have not seen any cases where the tune affected this. It is very likely the way the current exhaust is isolating or attenuating the vibration"
They do go on to say that with my setup they would recomend a PCV with a proper map anyway, and with the price they quoted I am inclined to roll the dice. Hell, I've got so much in this thing already what's another $330
