There was something interesting in a recent Dirt Rider article. They claimed to have updated their long term KX450 F, a 2006 model, but adding the spacers and longer bolts that the 07 came with. The 07 apparently has spacers and longer bolts in a lower motor mount that is supposed to allow more flex to happen... That is correct! And for around 40 bucks too! I did this mod to my buddies 06 KXF and he says he can tell a difference.