I just had my WRX tinted by Tint-Master in New London. They did a really fantastic job. It's been three weeks and they have cured perfectly, despite being the dead of winter.
The different levels of tint price reflect the amount of metal in the tint and thusly the amount of heat that it rejects from the sun. IIRC, the most expensive option of the 3 rejects 75% of heat.