Glad to hear you ended up getting the Vibe! As others have said, the windows were not tinted at all from the factory, so the tint is definitely aftermarket. Be sure to use glass cleaner that
does not contain amonia (it will turn the tint purple). I use Stoner's Invisible Glass. It's available at Walmart, etc. for under $4.00. It comes in a can of foam or a bottle of liquid (I prefer the liquid myself). Also, be sure to use a clean microfiber towel so the tint doesn't get scratched. On a bit of a side note, I wash all my microfiber towels (seperate from any other kind of towel) in the washing machine using only hot water and vinegar. I let them air dry. Using any type of detergent will cause you to get streaks when using microfiber towels on windows. Vinegar will get them nice and clean without leaving any residue on them that will than transfer to your clean windows, etc.

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As others also said, I would recommend just getting a seperate dedicated set of winter wheels and tires. We use 16" steel wheels (with OEM wheel covers) and 205/55/16 all season tires during the winter months (Chicagoland here) on both our 2009 GTs. The ride isn't quite as harsh and having smaller wheels and tires is better for cutting through the snow, slush, ice, etc. FYI, 16" wheels are the absolute smallest wheel that will fit over the huge front brakes on the 2009-2010 Vibe GT.
EDIT: I forgot to add that just as tpollauf said above, seeing that you're in Michigan, you should definitely consider coming down to Pontiac, Illinois for our
GenVibe meet the weekend of June 19th-21st. We'd love to have you and your Vibe join us!