And does it already have any UV protection? Will an aftermarket tint give more UV protection? Aftermarket tint will give privacy and more heat protection.
Plain glass provides some UV protection. I don't know exactly how much. It must block a lot of the UV because I've never gotten suntanned driving all day when the windows were up. It must not block all UV because dashboards will fade and crack on cars left in the sun sooner than on cars kept in a garage.
The glass roof on the C-Max is factory tinted, but not super dark.
I had aftermarket tint put on. Those tints often give numbers, for example: