Rust Proofing my '99 Camry

[jamesinator]

Hi everyone,
I just bought a '99 Camry CE in MINT shape. Not a spot of rust anywhere on the car, and only 160 000 km. (100 000 mi). It was rust proofed from the factory with that tar-based coating and it has never seen a winter, because the previous owner went to Florida every winter. I am now driving it in a part of Canada with pretty severe winters, and they dump salt on the roads. Would it be a bad idea to get the krown oil based rust proofing done? Or will the tar based factory layer still be good enough? Thanks a lot! Here's a pic of it!

[carsrus]

The tar stuff on the underside is pretty solid. However if you want to get the doors and other areas oiled its a good idea. The underside is pretty well protected from the factory.