The novarossi brands are Novarossi, Rex, and Top

Nova based motors, which means novarossi makes the motors to the specific companys specs, are RB and Mugen (there may be others that I'm not remembering)

If you want to get a good nova based motor within the $250 budget you have set, try the RB V12 3 or 5 port. They may not have the top end of a NS based motor but they are very driveable with the power to keep up with the NS based motors.