(ANSWER) I flew a J and a squaddie had an L besided me, the thing outruns the L and out climbs it, 100% fuel and no ord on both when flown... we fought also and the J seems to loop better than the L (ANSWER)
Balderdash.
Acceleration, climb, zoom climb and speed are identical in the game. If either aircraft is lighter, then it will have an advantage.
I've dueled some of the best P-38 sticks in the game (someday, I'll fight Delirium and Ack Ack and will complete that list). When I was in the L model, I saw no advantage towards the J model. Indeed, at higher speeds the advantage is to the L with its faster roll rate. Yet, even with flaps out flying just above the weeds, there is nothing one can point to that differentiates the two fighters. Which ever one comes into the fight lighter, that one has the edge.
My regards,
Widewing