Not sure how sturdy the various brands of long range tanks are but the one that you see commonly fitted on D1's is incredibly strong and rock resilient.

Going off road in my D1 in rough stuff on a number of occassions the old girl has ended up sliding down steep rock steps on the long range tank and apart from the odd dent or scratch it has stood up very well to the abuse and because of the taper on the tank it actually makes it easy to slide down some drop offs.

Sure no one wants to put dents or scratches in a shiny new tank but sometimes you may have little choice if your intended use for your D3/4 is to go seriously off road in the rough stuff.

Mind you I guess that is when having a modded D1 can come in handy sometimes, a few more dents and scratchs is not the end of the world on a D1.

cheers,
Terry