Hi. I recently purchased my '73 914. I put it on my garage lift and noticed that parts of the undercoating have chipped away. I scraped off the loose undercoating to the extent that I could easily do it, but it would take a lot of effort to scrape off the remaining undercoating to be able to effectively apply POR15 or something similar. There was only very minimal rust on the undercarriage, and I removed the minimal rust by wire brushing and "oxidizing" with chemicals. In this scenario, is the general preference to:

(i) touch-up the undercoating with shaker-can 3M undercoating, for example (i.e., keep undercoating on the car), or

(ii) not repair the undercoating, but instead paint the remaining undercoating and undercarriage uniformly (black) with Rustoleum paint, for example?

I want the undercarriage to look nice. With adding undercoating, I'm concerned that someone later will think I am hiding rust, which is certainly not the case. I live in Dallas and don't drive my 914 in rain/ice/snow, etc.

Thanks for your opinion and advice.

Take a picture of the spots for your future concerns and then touch up with similar material.

Good advice. Thank you.

Looks like you treated the rust well enough. I would just paint over and undercoat the areas that need it. Not need to scrape the entire chassis. Unless of course that is your goal.