It sounds like there is no problem getting an 03 Vinson manual. I think there lies you answer,if there is plenty of left over stock why produce an 04 . Suzuki has enough money issues or why would they be sharing resources with Kawi. I've seen this before in the late 80's with motorcycles where they skip a model year because of left over inventory. I have an 03 Vinson ,I've had zero problems with it . Plus this is not a new engine & tranny. Suzuki has used it in their prior 500 models. So don't be scared of an 03 , save some money, because if you want 4wd manual atv , there isn't alot of options out there.