If it is the standard size rotor, it is actually supposed to raise the kv slightly, if it is the 14mm rotor it is supposed to drop the kv substantially . This is assuming that the 4400 is going to respond the same as a 4.5. Which with 1/8 shaft was listed as 4800 kv. Then with the 5mm upgrade they changed it to 5000kv. Now they say with the 14mm rotor you can gear it up because of the lower kv and added torque.

That 4400 rotor was supposed to be horrible, your lucky it didn't blow. Mine was atleast the sintered 1/8th shaft.

If it was the 14mm rotor I wouldn't be scared to throw 5s at it. Novak did this to a stock 4.5 and broke 100mph in a street car, with their esc.