I think assembled coil overs are cheaper to install, shop time wise
Your front spring rate will be to low for a bumper and winch, if that's something you plan, also should be installed at same time, if not then 590# should be fine
-I'm on 700# springs and with an ironman bumper and winch its a...
I've had similar issues with rust repair, luckily mine was easily cut out in the rear quaterpanel.
I've treated the rust free metal with por15 and will have a buddy weld in a patch from eastwood.
I've had a hard time finding a shop to help me, and reverted to learning and doing myself
Michael...