I just got a 2015 Fit, and I was wondering how the underbody of the earlier Fits is doing with rust. I live in the northeast, and rust is a constant companion here. I had to get rid of an Escort ZX2 because of underbody rust.

 

Since the GD3 is made in Japan (and not in China) they have been holding up rather well to rust. Of course, you will always get surface corrosion on the exhaust system but I haven't changed the exhaust and have it checked for leaks every year and it's still good!

I'd personally get it rustproofed. Come and check out my guy Barry in Montreal. or find someone local. I recommend someone that uses grease and not oil for rust proofing. Grease doesn't leak or smell bad like oil and lasts for years compared to oil that must be redone every year.