2008 and later LTR450 if possible. The trans had some upgrades as mentioned I think, also the stock suspension was softened somewhat. Still a fairly hard riding quad, as it's really made for racing. We have a 2008 LTR that started as mine and is ridden by my son now. The thing flat out rips and we wouldn't trade it for anything else, except maybe a YFZ450R (gotta be the R). The wide stance on these is great and they make great power with minimal bolt-ons.