I am considering going from a yz250f to either a yz450f or a yz250 two stroke. I ride enduros and hare scrambles. I know this is a broad question but any input would be appreciated. Also does a yz250f flywheel fit a yz450f? I am also concerned about the 4 spd tranny. Is this a issue. And just so you know, I have been down the wr road and am not interested. Thanks.