My 93 accord auto LX (all stock) vibrates when the gear shifts. I have been told the engine mounts are going bad and will have to be replaced soon. I was planning on doing my second timing belt change this summer and plan to replace/fix the mounts at the same time.

Checked my local auto store who can get me all 4 aftermarket mounts for $150
A honda dealer has quoted me $350 for OEM mounts purchased online.

My friend suggests I use polyurethane inserts for $50 or just get a can of polyurethane foam $10 and ghetto rig it.

I am a bit apprehensive about using the inserts as they will make the ride very firm. I just want a smooth ride and prefer OEM but its too expensive.

Fortunately I will save on labor costs as I will be doing this myself with my friend who is a good mechanic.
Can anyone pls suggest any other option?
Thanks,
Mozzy