On my 95 i have violent shaking on hard acceleration if I start below around 30mph, once I'm over 30 I can floor it and it just goes, no vibration, perfectly smooth. I'm perplexed, does anyone have any ideas?

 

Simple things first.

Engine mounts.
Transmission mount
Tailshaft centre bearing/rubber.
Rubber (Jurid) coupling on the tailshaft.

This is assuming that the engine is running properly and not mis-firing on 1 cylinder causing the vibration, which from how I read your post appears to be OK.

 

I had a friend help me look at the car today and after climbing around underneath it he said the u joints were bad, very bad actually. I've never replaced u joints before and after doing some research Im confused. Looking at JDHT there appears to be 2 different ones JLM11718 and JLM1388. Now even if only one were bad it would probably be better to replace them all at once right? Should I replace CBC8996(Jurid Coupling) while I'm there as well? I'm just not sure which parts I need or how to replace them.

 

OK, first things first.

You have universal joints on the "prop shaft" and they will cause a vibration under acceleration. There are 2 and they are JLM11718.

There are also 4 universal joints on the "half shafts" which do wear, but the vibration you are describing would not be coming from them in my opinion. They are JLM1388.

I am a FIRM believer of "do it once, do it right", so I would replace the 2 propshaft joints, the centre bearing, and Jurid coupling. The vibration you are having may well be caused by the propshaft joints, BUT, they have possibly damaged the other 2 components by now, as you have been using the car with this issue for some time???????.

The Jurid is a simple bolts out, new joint in, bolts in.

The universal joints will require a press to do it properly, as will the centre bearing.