Johndeer, If you are just bashing around, you will want to run hard brushes, P94 style #RC4380E. They will last a long time with little wear on the comm. As far as springs go, you can run either reds on both sides or put a green on the neg. side (will give a little more RPM) Stonger tension on the pos. side. You can change out the spring tensions for tuning purposes. And I wouldn't adjust the timing to more than 5 or 10 deg. if for just playing, it will wear out the comm faster. You will also have to change the pinion gear to a lot lower tooth gear, like a 14t.