Voltage seems to be my main issue really- I have set myself up with 5s lipos and 6s A123 packs (equal to 5s lipo), so I really need an 1800kv motor ideally too. If you havent bought your batts or esc yet, then 6s lipo is ideal for the 1600kv motor and the MMM or another 6s esc. Otherwise, I would suggest 4s lipo and 2000kv with the MMM or some other beefy esc for a big truck/truggy etc. The MMM+2200kv motor system would also be ideal for 4s lipo, maybe 5s lipo, but 6s would be too much usually for an MT.