weather proofing?

Well I come from a cold climate where there is salt spread on the roads during the winter.. If you don't plan on eating off the underside of the car (ie show room all original appearance) then having the undercarriage rust proofing coating applied may suit your needs.

When my car was down to bare metal 11 years ago, prior to assembly, I also had the entire inside of the car covered with "rhino" guard liner, similar to truck bedlining material.

And then on the 1st day out of the paint shop, it went straight over for the undercoating.