If you arent going to run lipo, then its a no-brainer. But, seeing that you are new, I will give you "the 411". The GTB handles the same motors as the XBR but goes to the hottest of winds, the 3.5. The motors are different as well. The 13.5 with the XBR has a bonded rotor, where the one that comes with the GTB is more than likely sintered. For such a mild wind and from what I am hearing, the bonded for this motor is a little better. Sintered rotors really benefit motors when you get to the higher winds (6.5, 5.5, 4.5, 3.5). The other benefit is the motor handling. The XBR can handle the 8.5 maximum, whereas the GTB again, goes all the way to the 3.5. If you have no intention of going to the hotter motors, the XBR will more than satisfy your need for speed.