yes, only the 450r needs the mount cut off the frame, because of the offset rezzie, and i ran mine with a stock swinger and luv'd it, also, theres a brass nut type thingy down in the airbox, thats what the lid bolt threads into, when i had my stock airbox, that brass "nut" is held in place by a screw from the bottom, it started wearing thru the rezzie, pretty deep before i caught it, from rubbing, i removed the screw and brass nut to stop that, then just used a bigger sheet metal screw for the lid, so IMO, the 400ex is an easier mod for the same shock
heres a pic that shows the mount cut off.................