No, don't use petroleum based lubes on rubber. It will deteriorate them very quick. If you ever need to lube rubber, use a silicone grease.

If you're squeaking/creaking w/ stock bushings, and no polyurethane, I'm willing to bet you haven't broken all your suspension bolts loose, and re-torqued them with the suspension in the loaded position. If you haven't a lot of those bushings are loaded when the suspension is in a neutral state.

If you don't like the creak, don't get polyurethane bushings. I put a Prothane Total Kit on about a year and half ago with generous amounts of the "super grease" it comes with, and going over any dip, speed bump, etc... it is very loud, I need to re-lube them.

Joel Baldridge, ASE Certified Master Technician, Audi Certified Expert Technician