My $27 Et-Maxx !

Ok-a lot of "sniping" going on here...but,I am getting some good ideas here.I probably should keep the kit supplied 12 turns/blue EVX2 speed controller-for winter "bashing"...and use a brushless system for the rest of the year.
When "550" motors are being dissed,is that just the ones made by Traxxas?(Or,is it the size in general?) Can 540 motors be used? (singly or in pairs ? )