the "wonder bra" aka starshield, by 3m, is a good product, but it is a PITA to install and ahjve it look good...and does not have the impact protection a lined bra has.....i bought the bra straight from subaru, for my wagon. yes, it does have a big sticker on the box that says "not for use with the WRX" , but, i have no problems. the diverter things are ther to keep it from flopping around in the wind....and they do help. but, for 90 bucks...WELL worth the investemnt..even if it looks ugly.....it comes off in 5 minutes.
now, if you get a bra...heres some tips:
1. wash the car well
2. wash the bra well, first time
3. polish at least the hood, and fenders/front bumper....2 coats better
4. make sure it is dry on installation (car and bra)
5. if it gets rained on....take it off....it will wash dirt under it...scuffing your paint
6. wash your car often, take the bra off when you do, and don't reinstall till its dry.