My son runs the Ammo 28-45-2700 with an ACE 45 amp ESC.
He use's Venom 2100 20c 3s lipos. Rated for 42 amps.

It's the best flying heli I ever saw. It can go from dead stopped
on the ground to a 50 feet hover in the blink of an eye over and
over again. No strain...

He flys around for about 8 minutes and still has plenty of power
to safely land.

The motor is only slightly warm to the touch and the Lipo and ESC
are barely warm too.

That motor (Ammo), is rated for 500 watts. So its not really working
all that hard. It's truely an awesome, powerful motor. Very nice
craftsmanship too...

I'm gonna put my Medusa flight recorder on his heli and get some
real time readings on it this spring weather permitting.

As for a the Scorpion motors... I don't know... it would be nice if a
guy could afford to have one of each to test. I really doubt it could
be as good a motor as the Ammo.

These are my opinions based on actual experience with the Ammo.

Good Luck and let us know how it goes....

AB