1.) The Celica-Supra and AE86 springs are different diameters. You will nee to convert to AE86 perches. The upside is that you can use SR5 perches since they are the same, so you don't have to cut up a GTS rear end.

2.) There is no driveshaft that you can just bolt in, it will have to be modified. I ordered a custom 1-piece shaft through Illegal Garage here on C4ag a few years ago, because they knew the correct length that the shafted needed to be for the swap.

3.) You will use the AE86 4-links, and they should work without modification. What you will need is an adjustable pan-hard bar because the Celica-Supra rear end is wider than the AE86 rear end. T3 now makes a pan-hard bar specifically for the swap, but I am using their old bar and it's served me just fine.

The 4 links from the 86 will work on the supra rear end? No need to cut off the brackets?

They actually don't work slight fabrication is needed. Or for about 400 t3 also makes a 4 link kit for the swap. Direct bolt in.