Tip #7
Mud guards, these help keep dirt and mud from getting into your shocks, rear hubs, cvd's, a-arms, driveshaft, etc. These can be easily made from some polycarbonate sheet. I bought some online, but you can even use scrap left over from the trimmings off one of your bodies. This one is shaped to clear the wheels on one side and the body on the other.
Tip #8
Traxxas brushless E-revo ESC mount, this is a well made and secure way to hold down your MMM ESC. It mounts to the Losi battery tray very nicely and even has a place for the switch. The mount only cost a few bucks.
Tip #9
The battery wire and ESC power leads can get tangled or rub against the center driveshaft. I made a small lexan piece that is bolted to the center diff top plate and helps keep the wires from getting sucked into the driveshaft.