All the Novak motors are now sintered and have been for a while
It's only LRP/Nosram that are sticking with bonded rotors in their 5.5+
Dan I've run my 2wd with the 5.5L and 5 cells a few times now and it's just as fast, if not a bit faster than with 6 cells

I'm guessing the reduced weight and wheelspin let it accelerate quicker. It's as fast from mid-throttle as my 4wd with a 5.5R in