I just got my Lightning tail section today and will be doing a little powder coating and what not then installing it.
As far as modifications there really are none, it is almost a direct bolt on mod. If you are going from a Lightning to a Firebolt then there is some mods that need to be done but as you are talking it is very simple. The only thing that is different is the length of the latch cable, brake resivour down tube, and the tail light wires, but if you do as I did and trade someone who wants to do the firebolt tail on their Lightning it is all a direct swap so you dont need anything.
I will have picture soon but as I said it is nearly a direct replacement with no real mods needed.