Unless I missed it, did you state the timing setting for the MM? Would that affect top speed? I don't think any of the other settings would that I'm aware of.
What voltage cuttoff are you using? The mm will limit the current to the motor in order to keep the battery voltage above the cutoff, so the low voltage cuttoff a bit lower and do a speed pass. I once did a bench test with my MM and a weak 3s pack and when the cuttoff was set to 9.3 volts, it wouldn't let the pack go below 9.6 volts under a load.
Check out my custom converted 8ight:
Sub 7lb, lowest CG of any 1/8 buggy
I used auto lipo,12v and custom 12.6.But I used 2 different pairs of freshly peaked 8000mah lipos. I ended up with the Medusa and MM in my Emaxx.It's my spare truck that I let my son drive so it's about perfect for that.No motor heat sink,or fan on esc,geared 20/58.In 20 minutes of driving the motor was 107 esc 120. My Novak was 99 motor,102 esc.