RE: Engine Sizing
sdoering33, you seem much better suited to some kit and not a Traxxas Jato. Few people would describe it as big tough and powerful.
Can you tell us if you are interested in on or off-road applications? You should get a kit, or maybe a 'rolling chassis', so that you can add your own radio and engine.
Stay away from ready to runs, unless you really desire a specific model and it only comes RTR. For example, an Inferno GT from Kyosho only comes ready to run, and the car has no equal. Sell the radio and engine and add your own.
Ofna makes the DM1, which is a rolling chassis, and you can add engine and radio. These are examples.