$3500 sounds like a LOT for that amount of work. Mounts aren't too hard for the home mechanic; the bolts for the rear mount can be difficult if rusted in place. I'm a bit skeptical that the power steering fluid is that detrimental to the rubber in the mounts. Don't know if there are poly mounts for the Element. Did he say where it is leaking? It may be possible to repair the leak without removing the rack. Do use Honda PS fluid.