i have a 08 iq 600r and am looking at the bikeman 800 kit. what would be better to buy a stock new 800 out of a wrecked sled or get 800 cylinders put on. and what is the different between the liberty 800 and the new 800. and with the 08 iq 600r carbs why does the cfi port have to be welded to run 800 cylinders, thanks