Just my luck, I was ineligible for the last round, which I knew, but, now that I am eligible, I'm not sure if I can identify the Rust, although I'm pretty sure of the Hint. Oh well, here goes:
Rust 29 was correctly identified as a Saturn Sky.
Hint 25 says: A badge-engineered version of this car was the namesake of another car that was built at the company where the next vehicle in the chain came from. The Opel GT, built by Opel, was a badge engineered version of the Saturn Sky.
I think Rust 16 might be an Opel, possibly a 1960/1963 Opel Record A.
So: Hint 25 and Rust 16.