hi everyone i have a revo and have heard a few people say that they up grade the reciver pace i have have the stock battery pack and was looking at other ones and there all 6 volts but diffrent mAh what affect will i have by changing it

The higher the mah the longer it will last. I run the stock Traxxas pack with a personal transponder and JR 9000 digital servos at it works just fine. No need to waste your money on a battery. Buy some tires and shock springs diff oil and shock oil.