I have both the Mopar bra and the Speed Lingerie bra. The Mopar bra is much easier to install and far less potential damage.
I have used the bra many, many times over the 8 years I have had the RT/10. I have experienced some road garbage that would have made a mess of the fascia and the bra protected it. I know of another owner that hit a raccoon or other animal and had no damage either. From my experience I would recommend a bra for long distance drives when the potential for debris is fairly high. I would not use on in town in normal use.
I would never, that is NEVER, leave it on for any extended period. I have removed it daily when taking a long drive. If it gets wet I would remove it as soon as possible and not reinstall it until everything is dry. I vacuum it or brush it before installing to make sure that no trapped debris is placed on the painted surface. If you use it wisely you should not incur any damage. Note this is coming from a Viper owner that has used one more than 50 times and more than 8000 miles.
The Speed Lingerie bra has a potential wear problem. The hard, clear portions that cover the driving lights can find its way onto the painted surface. If it does it can wear down the clear coat and eventually wear in the paint. I have placed soft material in those areas to protect for that issue. I like the Speed Lingerie bra appearance much better. From 50 or more feet you can hardly tell that a bra is installed. That is because it uses red material that is pretty close in color to Viper Red.
Good luck in whatever choice you make. Just remember this is not a Honda. A bra is intended to give temporary protection and not make an ugly car look a little more "high performance."