Ok, while I don't have experience with them on a snake, I can say this much... A bra causes more damage than it prevents. The first downfall of a bra is that they trap dirt under itself and will scratch the paint when you remove to wash the car. 2nd problem is that they do have to be removed and cleaned every time you wash the car. If you don't, dirt and moisture get traped. 3rd, a black bra acts as an oven. Moisture under the bra gets traped, then heated by the sun, creating a steam bath for the paint underneith.
In general, unless your just totaly paranoid about chips and have extra time to pull a bra off and on, don't bother. In most cases, it's far better to keep your distance and watch out than put these dirt magnets on.
Dd I mention they were fugly? Beautiful Blue/white GTS...that curvey rear, that sleek roof, that muscular hood and that.... flat black vinyl thing that has leached itsef onto the nose like a parasite... Yechk!
You must be registered for see images
The only way I would use one is for a long trip, where it would be removed when I got it to my destination.