I would say all you need is the springs, shocks and struts, and the plates.
I have my 86 lowered on 2.5 springs, but original shocks and struts, and it's OKAY, but if I hit the right bump, it WILL bottom out the shocks. I don't have too much camber problems, but my buddy has an 04 gt lowered 2 inches, and he needed the plates, it had way too much negative camber.
On a side note, anybody know how much more drop I'll get if I remove the isolators? It's an addiction. You can never get low enough..
1986 GT with the typical poor boy mods. 3.73s, Hurst short throw, King Cobra Clutch with aluminum quadrant, lowered two inches on Eibach springs, Hopefully adding some heads and a decent intake soon!