If you need to be R.O.A.R. legal you have to run 4 cell (in a hard case). With 4 cell, a 2200Kv too 2600Kv motor would be the range you need. I don't care about ROAR. I run A Neu 1512 3df (1700kv) with 6S 2600 mAh cells in my MBX6. The mains at our local track are all 10 min or less. I used the RC Products design MBX5 conversion kit (required me to drill some new mounting holes in conversions battery tray but not a big deal). I'm using the Mamba Monster ESC's in all my set-ups.
P= I x V
If "V" goes up, "I" goes down to get the same amount of power.
I've had my X6 since september, run it every weekend. Have'nt broken to much stuff.
-EMBX6,T8 1400, RX8, 5S Lipo ,Elite-RC, RCM tray
-EMBX6,T8 1350, RX8, 5S Lipo ,Elite-RC, RCM tray
-ROAR 4 cell rule Blows