Wow, it looks brand new underneath, even the brake discs & exhaust. If mine looked like that I’d be tempted to get it professionally sprayed with rust inhibitor by someone like Krown http://krown.co.uk/uk/krown_application/Rust_treatment_processSaw this incredibly clean Z3 2.8 on the Bay...
In order to help protect it from the environment which parts need to be sprayed and with what?...it all looks very bare metal at the moment....