One of the most common modification to have more brake and more steering is the forth channel mod. This is also the cheapest and easiest mod you can make on your Monster GT.
The only thing you have to do, is to take the battery connector from the receiver and connect it into the #4 (AUX) connector. This will bypass the 4.8v BEC and allow all your servos to work at 6.0v.
This modification is not reserved to the stock receiver. In the case you don’t use reverse, you can connect the battery connector to the third channel of any receiver. This will also provide 6.0v to all your servos.