Look into ceramic tint... it's not cheap, but does a WAY better job than anything else out there. Mothers is about the best here as they offer the lifetime warranty. You WILL lose radio reception with anything you go with (FYI)
2002 WRX Sold
2007 WRX Sold
2007 STi totaled
2007 Foz XT sold
On our cars the the radio shouldn't be affected. You can also get tint that doesn't have metallic flecks in it and it won't affect it. The only real things that would be affected are the AM radio (slightly) and satellite radio or car phone antennas because the metal in the tint blocks the transmission of the signal. Correct me if I'm wrong, but I believe all the WRXs that got SAT radio had an external antenna (I know mine does as one piece for the AM/FM SAT and NAV altogether). Ask around about non metallic tint. I only recently heard about it the last time I got my windows tinted. I don't know what brands are good though, sorry.