there are drawbacks to a light crawler. Like you mentioned, the more weight the more traction. Most people's rigs are around 5 pounds, i am not sure about mine, but running weights in the tires and the battery over the front axle help out a bunch. Getting the wieght on the front is critical. Not having a budget is nice, i dont n\know too much about gear reduction units myself, but i do know that the gd-600 is a proven design to get a good gear reduction. Running a brushless is always nice. The thing that is a problem with high gc is that the tranny is mounted in the chassis, and that is also one of the heaviest items on a crawler, the higher that is the more of a risk to flip over. I have found that about 2 3/4 clearance is quite adequate. A better cog is better than gc. But you have to find that happy medium, which i believe to be around 2 3/4 in most cases!