So when doing the work on my car I was out of money but had a problem with my rear diff "knocking" under acceleration (meaning the rear diff bushing had failed). So here is a creative method my buddy used to fix it and after driving it for months I must say it works great:
I basically cut some slices off a hockey puck and installed them in the free space in the diff bushing, the top and bottom. I installed a piece in the top, then jacked the diff up which compressed that piece and forced another piece in the bottom. I did this with both bushings and when I was done the thing was not moving at all even with the weight of the car on the diff. I then bought and used some of this 3M window polyurethane sealer which gets really hard when it dries and filled in all of the other gaps. I then covered it all up with some large washers. When it dries it should be firmer than stock (STI time). I got the idea for all of this reading a bunch of forums. I guess the 3M stuff is really popular for making more ridged engine/trans mounts and stuff and is really durable. People have also used it to stiffen the diff bushings. Pictures attached.