We haven't weighed it, but is reasonably light. On the test flights we did not inflate the retract system or fly with gear up, but this is imminent. Note: Nosewheel unit locking pin needs attention, be sure it locks in place - we had a few flights were the noseleg fell out and hung only by the wires. Stalled-out landings on grass prevented any damage. For strength, also use metal quicklinks between nosegear wires and steering servo.
I anticipate speed improvement with gear up and engine cowlings in place, but it does nice big loops etc. as is. Unlimited vertical is hardly a scale requirement for a P-38...
The engines we use are plenty for this model, would hardly recommend weighing it down with much heavier power plants. One could use YS63's if the extra cost is ok. Equivalent two strokes might also give a speed improvement, but would require IMO in-cowl mufflers to maintain scale looks.
Now we are installing a RAM machine gun sound module for those low strafing runs, plus we are producing aluminium guns/cannons for the nose. Functional oleo legs will also add to the P-38's appearance.