The a-arms won't work, the spacing is greater on the 450. The shocks might work, I held up the front set off of my 400ex and it sure looks like they would bolt up, but I heard somewhere that the geometry was wrong. Not sure about the swing arm. The rims will bolt right up. I think that the 250r grab bar will fit also. Of course the handlebars will fit. The front bumper off of my 400ex will bolt right up, I used my 400ex bumper until the one for the 450 came in. Thats all I know that will work, there might be others. Does anybody else know of any more parts that will interchange?