It has been done. I believe there was somebody on here or the Kawi forums that had a 2nd gen in a first but didn't say much about it. The biggest issue is mounting locations on the heads are different. I'm not sure but you will probably have to swap the ecu's, tbi's, and gauges. Little things like the speedo pickup is different, tbi spacing etc... You can try checking out Garth's page as he did run a 2nd gen head on a first gen engine. I'm pretty sure he also ran the 2nd gen tbi's and may have figured out a solution for the mount.