If you have an automatic and want to brake torque make sure you only do it like 3 times in a row max at one time otherwise your tranny fluid will begin to really heat up and boil. The major source of failure with autos is heat not necessarily parts grinding together like in a manual.

I used to have an auto Subaru wrx (mistake) till I wrecked it. Anyway you can imagine auto with a low compression 4 banger engine with boost that doesn't kick in till 3000 rpm = one slow mo fo off the line so with an auto wrx brake torquing was a must. The secret to keeping your tranny alive is by getting yourself an auto tranny cooler and using syntheic auto tranny fluid. The synthetic fluid should withstand heat levels many times higher than regular fluid that coupled with the cooler should make brake torquing fairly safe to do on a semi regular basis.

If you want the same kinda performance off the line without brake torquing then you need to get an upgraded torque converter from an aftermarket maker like level 10 or Protorque. This will launch your car at a higher stall speed without standing on the gas just mash and go. Your car will launch at the higher rpm levels. When you do this mod if you also press down on the gas you'll be able to launch at an even higher rpm. Say you choose a 3000 rpm stall convertor you may launch w/brake torque at 4500 instead. The draw back to this is day to day drivability. It'll be slighly jerkier. There are other mods you can do such as valve body and line pressure mods to the auto that will sharpen and speed your shifts as well.

Upgraded torque convertors and valvebody jobs are major tranny jobs and you might not wanna do that on your new car but you definately should do the synthetic fluid/tranny cooler combo mod. No drawbacks to them either if done right. Just make sure the fluid is compatible with stock specs and cooler is fitted well with the car. I've heard that some folks in extreamly cold climates have their trannys not get into operating temps quick enough with a cooler like this since it works so well but that's the only drawback I can think of. Unless you live in a really cold place I wouldn't worry about it. You'll get more fluid volume capacity, increased cooling and performance, and probably better gas mileage. It's not hard to install either I think any shop can do it even a uhaul truck rental shop. They use those coolers all the time in trucks that have heavy loads to pull so you know the technology works.