I'm really happy with the 450x so far. I bought it last March and rode it almost every weekend until November with no problems at all other than it had a bit of a bog. But I changed to a Boyesen Accelator pump cover and that helped reduce it. I also installed a Kouba lowering link as the bike was a little tall for me. I would like to get a bit more power out of it (my last bike was a CR500) which is why I'm looking at the cam change. I haven't been out riding yet but I know some guys who went out last weekend. The snow is still pretty low on the mountains so the riding areas are a bit limited right now.
I was just at my dealer in Kelowna BC today as I'm looking at putting the "R" camshaft in my 450X. He rattled off the other mods that I should do to get the full-power benefit. In addition to the R header pipe, air box mod and jetting changes, he mentioned something about a pink wire mod.