Tip: In the case of the Castle motors, the name/number designation 4600, 5700, 6700, etc. are the motors "kv" which means 1000's of rpm (the "k") per volt (the "v") so if you look at the 5700kv motor, that thing will spin over 60k rpm on 11.1 volts, over 40k rpm on 7.4 volts. Have a look at the 4600kv motor, with modern batteries you'd need a really high traction surface to harness much more power than that.
If you're new to RC, especially racing, you will enjoy yourself more with less power. It's tempting to get the fastest stuff (it doesn't cost any more, right?) but you will be frustrated at how hard the car will be to drive and most likely lose interest than if you get something that you get around the track more easily when starting off.