IF you want to use the internal bec in the pede buy a short servo extension wire and remove the red wire. By doing this you can remove the extension when the esc is in the pede and still run the internal bec, but when it is in the Maxx you can use the extension to eliminate the red wire.

You can also use some micro deans so you don't have to solder the bec straight to the battery leads. By doing this you can use the bec in the Maxx, but you can have the option of not using it in the pede.

IMO these are the best ways to use one esc in two cars.