Headers vs 360 manifolds for 318

yep, the jegs setup is very good for the price, beer and some interesting language and they work out pretty good, better price than the muffler shop
Do they come pre bent and everything? Just piece it together? The car currently has dual exhaust I'm not sure what size I wanna say 2 inch maybe 21/4. It has two new (15 years old but never ran) thrush mufflers. Not glasspacks actual thrush turbo mufflers not even sure if they still make them lol. I was gonna weld in a x pipe and work forward from the crossmember back it's all there.