Noah,
Have a very good friend whose Father in Law owns one of the most famous P-38's around. Guy named Lefty Gardner is one of the first members of the Confederate Air Force. He is an icon in the industry and unfortunately in his twilight years now.
I hired his son a few years ago, we became friends and he promised me a flight in the -38 when I was in the area. Fast forward two years ago and Darren's brother Ladd was flying the plane from an airshow in Tenn back to the family home in Southern Texas and one of the turbo/superchargers came apart and caught fire and he had to put the bird down in a field.
http://p38whitelightnin.com/accident/
http://warbird.com/lefty.html
The bird is being restored and eventually will be back in the air.
About the -51...
Speed it had and lots of it. If you kicked the second stage of the supercharger in below 12,000 feet it had so much torque that it would cause the plane to roll from the increase in power.
Maneuverability? Well, the Spit or FW would fly circles around it.
Firepower? It had eight .50 cal Brownings on it and thats a lot of power but almost every other countries fighters had only cannons or a mix of cannons and machine guns on them. Planes with cannons carried a lot less ammo and rate of fire was slower. If you got hit with enough .50 cal bullets (or just one in the right place) it would down the plane or pilot. If a plane got hit with just one 20 or 30 mm cannon shell it rarely was able to stay in the air.
Best way to equate the -51 to the other fighters of that period is that it was like the cars that America made then as well as now. Very good in most cases and fast in a straight line. Take a lot of punishment and will get you home. Compare most of them to a 911 and they are just different. Fast in curves and a straight line and very fine and well tuned machines.
We won the war not so much because our tools were better, which in many cases they were not but because we overwhelmed them with so much force on all fronts. Being right did not hurt either but their men were just as dedicated to stay alive and win as ours were, at least early on in the war. It helped that their leader was an idiot and made stupid decisions later on in the war but in the end there were just too many of us versus them and our leaders made the right decisions.
Another way to point this out is our tanks of that era. The Sherman tank had a puny 75mm main gun and compared to the Panzer was terrible. The 88mm gun of the Panzer was excellent and one of the best for many years. They could knock out our tanks 500 yards before our tanks could even fire on them due to the range of the 88mm versus our 75mm gun. It was only when we started putting boatloads of the Sherman on the battlefield and overwhelmed them on the ground as well as controlling the air war that the tide of battle started turning.
The P-51 was an excellent plane and it really came into its own later on in the war when it was re-engined with the RollsRoyce Merlin engine. With that and the drop tanks it was the first fighter in the war that could escort the bombers both to and from Berlin. This way the Luftwaffe could not ravage the bombers and the allies finally had the ability to bomb both day and night and slow the war down. Interesting thing is that German production in some parts of 1943 and 1944 increased over that of the earlier part of the war. Only when we started hitting them day and night did it finally take effect.
Enough rambling. All the old WW2 planes are interesting and everytime I get the chance to fly/ride in one I am all over it! If you ever get the chance to do it, its well worth it!
Joe