Best setup for Truggy.

Hi, i am just thinking of converting my Truggy to brushless.
As I am new to this brushless setup as I have always had nitro, i am not too sure what to go for.

Basically it is for racing. i want to run it on either 5s 0r 6s
I have been doing a bit of searching around and have decided on these two brands of motors.
Tekin motor/esc. or the castle creations motor/esc.

Just not sure wich motor to go with.
The Castle Creations basically only have two to chose from.
The Tekin have a few more.
I guess also while I am here, what size gear I will need for the motor.
( The spur is a 50T)

If anyone can help me out here it would be greatly appreciated.
Thanks.