Just seeking opinions. Would you undercoat you classic, if it already has been undercoated in the past, and looks crappy? (had discoloration, dirtish and has paint overspray)

 

First I wouldn't undercoat a car that hasn't been undercoated before. I think it just creates a place for moisture to get trapped under and also covers up the real car parts. That being said if your car has already been undercoated you have some options. You could go thru the pain staking task of using a solvent and removing the old undercoating and then painting and detailing the whole underside. Another option would be to clean up the old undercoat, remove loose pieces, remove the paint overspray, and put on a very light coat of new undercoating in areas where the old has completely fallen off. After this all drys you could paint the bottom with a semi-gloss black just to make it all match. This option would just be to dress up what you already have without to much work.

 

x2