I agree with earlier posts that without increased power, a heavier pony would be like flying a p40 with 20mm's. Personally, I would love cannons on a pony but I do alright with the 50cals. As long as you are talking about adding a version that saw little if any combat, I would rather see the p51h included. It was 600 lbs. lighter, much larger rudder, even better visibility and had the uprated Merlin V-1650-9 w/ WEP rating of 2,218hp (although non-WEP was slightly lower). This thing would have been a beast and I would be willing to "settle" for 6-50 cals. w/ 1,880 rounds!