Rear Irs

The black rubber ones are a slightly softer compound than the red urethane and will transmit less road noise to the chassis.   I think Berg still sells some HD versions, if not, then where-ever you get them they're about the same.

For lube, I've used the silicone grease for Urethane.  Yours should have been lubed with the Urethane grease when installed.  If not, they'll squeak like hell.   Even when using that (maybe especially when using that), I've found that they dry out and start to squeak in about two years.  I've been using CV Joint Grease on mine and after three years+ they're still reasonably quiet.  You might try that, but you'll have to pull the 17mm hex bolts, lube everything and put them back in.  It would be wonderful if they had grease fittings on them, but no luck there.

I've never found a spray that made them quiet.

I can't recall them coming with any grease but it was 10 years ago. I'll pull them over the next coming weeks and inspect. If they look good I'll try the CV grease method Gordon.

I know those things drive me nuts as they always squeak at some point.  There is a grease that is waterproof 

AquaShield Waterproof Marine Grease 

http://www.thebuyingnetwork.co...ld-Grease-s/1819.htm

Prothane  Bushing Grease?

Is that a better grease Bill?  I find that after a few years your back at it that is one of the pains of the IRS.

The Prothane silicone grease will last a couple of years and then they'll squeak again.  I have yet to find a good grease for these bushings that lasts more then 3-4 years but CV joint grease is my winner so far.  I use it on the front trailing arm-torsion bar bushings, too.

Every greased joint needs to have the grease reapplied periodically. In this case, the car was not designed for greased bushings (zerk fittings) so there is no way to reapply the grease without disassembly. Spraying stuff on the outside isn't going to do anything because you need to get the grease on the actual sliding surfaces.