I have a color-coordinated Speed Lingerie for my Grand Sport and really like it. My husband recently bought a 2002 convertible and has been reluctant to spend that kind of money for a Speed Lingerie so I went ahead and ordered one for him...he doesn't know anything about it, so don't tell him!!
One of the biggest drawbacks of a bra (other than being just plain ugly for daily use!) is if it doesn't fit the car very tightly. If there's any play, that play can cause paint damage by slapping against the car at high speeds. The SL bra/mask fits the car literally like a glove.
There are many brands out there, and I'm sure you'll hear from those who have them. Whichever you buy, don't make a habit of using it just around town...trips are the only time the bra goes on my Diva! Also, if you happen to get caught in the rain, be sure to take the bra off as soon as possible and thoroughly dry the car.
Good luck!
Elaine