This subject has been cover on the board for many years now.
It's typical symptom of after-martket axles especially in the MY95 I had. I had to keep the front windows up a little in the rubber at the top of the door sill to keep them from ratling loudly at idle in gear.
I'd be inclined to have the idle RPMs verified. A low idle of 400 rpm would exasterbate the vibration problem, and a higher idle may help but not cure it.
A tired or lazy coolant temp sensor caused my 95 to have a varing idle that started too high cold then dropped too low at operating temp. Once I replaced it the idle stayed around 750 rpm after warm up as I recall (since this was about 6 years ago).