1994 st auto Shaking Options

[Noahwhite2014]

Basically when warm, and at a stop light occasionally the rpm drops to around 650-700, the steering wheel shakes and i can hear the interior plastic also shaking. I can see the hood shaking as well. Usually at stop lights it drops to around 800 rpm and there is no shake. It doesn't stall, it doesn't sound or feel like it will, it just vibrates the whole darn car.

Known issues:
All 4 engine/trans mounts have cracked rubber - anyone know where i can get a good set for a reasonable price? Being that i live in hawaii rubber that isn't indoors pretty much need replacement every few years... so i was also wondering if filling the entire area that was rubber (on the old mounts that i clean and remove everything thats not metal) with silicone rubber would be an option, it would allow a lot more movement though, just curious due to the fact that silicone rubber lasts a lot longer in my engine bay. I was looking at poly filling engine mounts around the center of the mount, then filling in a thinner layer around it with silicone to dampen the vibration, but not allow as much movement as just silicone rubber, and it won't be as harsh as just poly. But id still have to redo it all every 5 years or so, since the poly will still break down just like rubber...

But anyway
Ive replaced spark plugs and wires, air filter, oil and filter, the usual stuff. Cleaned the throttle body and EGR. What else would help smooth out the vibrations? A new fuel pump, new fuel filter, cleaning injectors, and the entire intake manifold/runners?

I wanted to clean the manifold, but had a hard time removing it.

What do you all think?