POR-15 is usually available from Canadian tire these days in the quart cans.
I have never tried the chassis saver, and the reports from the web are mixed, with the owner saying they are the same and the odd guy saying the chassis saver is lacking. If they are the same, then it is possible to get bad results with both from as little as a drop of perspiration falling into the can.
While the POR-15 is cheaper by the gallon, too often you will just end up with a huge hockey puck after opening the can a dozen times, or having to destroy the lid to get it off after the paint adheres it shut.
A quick online check shows stock in all the Ottawa area Cdn tires. I personally like checking for stock online. Otherwise, I drive all the way to the store to find they are out, and then spend money on stuff I didn't know I needed.
http://www.canadiantire.ca/en/automo...ontent=Default