I had already got Shelby coils from Tony Branda so I went the lowering route and cut a full turn off the coils. I also have lowered my upper control arms. A full turn was a bit too much off the coil. I should have maybe only cut 1/2 a coil. I wound up putting the taller poly coil insulators up in there and I'm happy with it now. I also just got 5 leaf mid eye rear springs that I haven't installed yet.
You can see my 65 fastback at: http://hottarod.stangnet.com/
You can see my 65 fastback at: http://hottarod.stangnet.com/