Sup JOE!!!!!
Basically if you buy a b20 motor all you need to do is use your LS
Intake manifold
Distro
injectors
alternator
and harness
Basically everything that is hooked up to your LS Plus your flywheel and clutch since the b20 is off a AUTO. It's extremly easy swap. Nothing hard at all. Nothing to re wire or anything. I don't think your motor is messed up nor your cams. It would take at lease 1,000,000,000miles to wear them down. goodluck. If you need anything pmme