The major mods for the bike arent for more performance instead of reliability, like strengh treatment for the transmission, nicasil or something to make it less drag on parts and some gears of the RZ to make it ride faster than the banshees ratio, lots of lbs. from gusseting the frame and big skids to protect the belly of the quad
Before the banshees dominate that race I have lots of old mags that made tests of banshees for the baja, they had 13.5" front suspension travel !! and were very tall (before the ZPS thing)
I dont know why privateers don