i say stock losi , associated , traxxas, tamiya that way you have somwthing for everyone and the most important thing to know is that you dont make that good of a profit on the acctual kits or RTR'S the real profit is made off the parts!! so you want to have plenty parts in stock for all the brands you carry at all times. the mark up on a car is maybe 15% but the mark up on a set of a-arms is like 300%- 400% if not more! so the money is in the parts, there is so much money in the parts that i have thought of opening a shop with just parts!