I already had the Mamba 5700 and Mike designed the chassis to fit the 4200 2s2p perfectly with the Max behind it. He did, however, put two nice long lines of mounting holes to make it an easy swap to other battery configurations; just won't have alot of room left behind standard size 4-6000 mah cells. I don't think I would want the added wieght of 3s for racing purposes but it would'nt hurt my feelings if there was an L motor available with a kv around 5500; the mamba gets a pretty good workout.