Be aware, tinting doesnt actually stop heat from getting into the car.
The sun is heating the glass, having film behind it wont actually help.

Tint however will cut heaps of glare, save your upholstery, and also look good!

Oh and if you can live without tint on your rear window, then dont get it done. They cut my rear demister doing it, and reversing at night time is horrible due to the E34s poor reversing lights in unlit areas.