just bought '00 WR400. With the help of some friends with YZ's have modified in the following ways. Removed stock rear fender installed YZ. Replaced stock top triple clamp with YZ. replaced head light with YZ number plate. Replaced stock pipe with '99 YZ400. Odometer removed. Odometer drive replaced with YZ spacer. Result is 8# lighter and quiter than stock. Leaving the WR bottom end on a large tank YZ. On my yearly trips to Colorado I plan to install the headlight, spark arrestor and odo. Meanwhile, I have after market plastic that will keep my stock stuff new untill the big ride in the mountins with all my buddys. The cost was small due to these good buds.