You can use this too

MicroDan(www.gobrushless.com) 2900kv with a E-Flight 60 amp ESC ....has to be E-Flight due to the switching rate REQUIRED by the motor (16hz)

This one I have used very light and very fast ...not cheap but worth the money

I looked at hobby king and they are out of most of the super cheap motors. You can use any of the 28 mm motors. You need to look for a longer motor and check the specs. to see if it will run on 4 cells. You can run a motor disigned for 3 cels on 4 cells.... BUT it will get HOT..REAL HOT..if you do not have a heat sink and a tons of air flow.