Would it be worth it to dynomat the bottom of the car. I think this would make for a long lasting, non rusting surface. Is this a good idea?

 

The undercarriage, outside the car? I wouldn't spend that much money. They make underbody coatings you can put on yourself that'll cost you about one tenth of Dynomat. It's not like the undercarriage tends to rust out as is...

Best of luck!