Motor power question

[scoyle]

I have two questions about motors for my 8th buggy... I have ended up with three motors to get me running;

Reedy Sonic 1512 1800kv
HPI Flux Scream 1965kv
Turnigy 2200kv

The only one I have run so far is the Reedy and you can see it here;

http://youtu.be/d-Oyf2nQnd4

I have the motor attached to a Hobbywing Ezrun SC8 speedo.

My questions; is it just the KV that is used to differentiate the power - so are my three motors going to be good steps up in power or does the can shape etc matter?

My second question is whether there is a good way to connect the motor to the speedo so they are easy to swap in and out? Two of the motors have solder tabs and the HPI has hard wired wires. Is there such a thing as a three pin deans/EC5 type plug if that makes sense?