Can you put 1996-1998 Mustang Gt taillights on a 1995 5.0? I was thinking of doing so for a newer look. Is there any new wiring that would be needed and would they fit the same?
Yes you can, and yes you'll need to change or alter the harness (more bulbs). Many (myself included) would say the 94-95 horizontal lights were the best looking. They're also fairly expensive / rare, while the 96 & up are pretty cheap and easy to find.
The 96-98 tails will fit just fine, but you'll either need to buy them with a wiring harness or you'll have to make your own - I believe the 96-98 tails have an extra bulb somewhere. You can get a step-by-step set of instructions here:
I changed mine over years ago when a guy backed his truck into me and I needed to get the number and one light replaced. Still have a couple pairs of the old style lights lying around. It's a simple 30 min swap if you get the harness from a parts car too.