Diff Dilemna! Need opinions!
I can recommend the Ranchos that Calvert sells for rear shocks. Or at least they work decently awesome on my car. Cheap too.
Another big factor in getting rear end stuff (and transmissions) to live is choosing the right clutch. And that T-5 is going to need all the help it can get.
I don't know what the flywheel you're using calls for, but if its compatible, I highly recommend the clutches that these guys sell.
http://www.promotionpowertrain.com/NEW_FORD_CLUTCH_PAGE.html
If that pressure plate won't bolt up, maybe they could point you to one that will. These clutches feel like something out of a Honda Civic (with a cable clutch setup even) and I've run 10 second quarter mile times with them.
Steve