If you are planning on racing the SC10, just get the brushless Novak Havoc 17.5/13.5 or the 8.5 (for mod class).  It's $130. or so for the ESC and motor.  Whatever class your track runs the SC10 in.  If it's just for bashing, get the 8.5 or get the sidewinder + 4600 motor if you want a little more power (with a 3s LiPo).  Now there is also a Havoc 3s but that is a little more expensive.

There's no crime in thinking over a purchase before you make it.  I would not waste any money on brushed motors as you will just end up tossing them in a few months.  Brushless there are pleanty of people still runn the exact same motor and ESC from 3-5 years ago.