using your car in wet grass, snow and puddles can be hazerdous if any of the water hits the electrics is the wrong places. there are certain precautions you can take like putting a balloon around the electronic parts but since i have never done this maybe someone else will be able to detail this a little better for you. using it in long grass there is no problem at all people do this all the time and never have problems. as for gravel and the beach i am not 100% sure. thing is they have brought out rally cars with the sole purpose being to drive on gravel. and thats is what they seem to be used for so i dont think there will be any problem with this. but then again it may get in and damage your car. i am sure in the dvd you get you see the rush being used in and around some light gravel pits and places of the like. but after you are finished there will be a hell of a load of cleaning to do.
.steven.