Hi, may be a bit late, but here is my experience. I have an RC8 with Castle 2650Kv with MMM Esc, and is running nice with a 13T pinion (73 km/h). No problem keeping up with nitro guys
. The MMM has broken, but you get a new one from Castle for $70. The motor is still going strong, run a lot since April. However, I have a new 2200Kv ready, and will use that one next season (with 16T or may be 17T). Have fun!