What bl motor to use with 3s lipos

[SpEEdyBL]

Are you sure 55 is what you are looking for? What was your previous setup? Most 2wd vehicles can't even reach that speed unless you are running at an airport or a perfectly smooth parking lot and 300 feet of radio range. Otherwise the vehicle will just wheelie unless you carefully guide the trigger to full throttle. And you definately can't reach that speed offroad. Anyhow 55 is doable with the 4600 incase you are still in doubt, but you will have to watch the temperatures as you would with any setup geared for 55.