My question might be, what tires do you intend to run during the winter months?
If you are stating your summer/all-season - then I'd yell and say NO.
Fine, Toronto might not get all that much snow/ice - but the safety of proper winter tires during those months would far outweigh the notion of selling them for me.
Course you can always try downgrading the oem and hopefully profiting.
Meaning, sell your 17" oem + tires and purchase a 16" + tires set. Wouldn't give you all that much altogether, but you have ample time to find the right combination you'd like. Basically start looking on sites (here, nasico.com, toronto-subura-club.com, kijiji.ca) and deciding...
I'd always prefer to keep the two sets of tires separate as it makes it cheaper/quicker in the long run to change sets. And running 16" tires is cheaper for the rubber than 17"