To make the driving realistic I've added metal, tracks roadwheels, suspension uppgrades, dual batteries and so on to my Tamiya King Tiger. Now it weighs +8kg's. To cope with the added weight I fitted Impact gearboxes but changed the piniongear from 10 to 8T, that will give the total ratio of 130:1 instead of 105:1. The Impact suspension is also adjusted so the first two set and the last three roadwheels are softer than the rest. Just to make it rise in the front while accelerating and climbing. Also fitted Turnigy chip last weekend, that helps alot. It's slow, but my HL Tiger 1 is even slower with the 3:1 gearboxes with black capped motors, it's also much weaker.(I use the same battery type)