The P-47N is the most capable Jug all the way around.
1) First, remember this dogma: "Tho I shall fly through the valley of death, I shall fear no evil, for a clean November Jug is a fast mother f-er."[at any altitude]
2) If you husband the WEP for when its truly important, the N is always faster than about 3-4 planes in the game, at any altitude
3) Once you have the P-47N at about 1/4 tank of fuel, with perhaps half of your ammo remaining, you're beginning to approach Spitfire-esque levels of wing loading and (on WEP) power loading.
4) 7,000 feet above ground level is escape altitude--if you have this much altitude, you're only about 8 seconds from showing 500 mph after a WEP assisted dive.
5) I take 75% internal and no drops with the N, as I'd rather have the induced drag of the extra weight than the parasitic drag of the drop tank. I have no scientific evidence to prove this is more efficient--just my gut. As soon as I rotate and begin to climb, I immediately switch to the wing tanks, and burn off whatever is left in them at the 75% fuel condition. After they are empty, the Aux tank goes next. I like the maneuverability advantage over the fuel-leak prevention technique.
Lastly, I love this plane, but have no idea about why it has a 5 ENY. I believe the N Jug deserves a solid 5 OBJ rating, but a 5 ENY is a bit low. When I began playing AHII, the P-51 had a 5 ENY and the November Jug had a 12 ENY. I think those are probably correct, but I'm not HTC. Also, given that the OBJ rating is what is used to govern attack scores, the 5 ENY cannot be related to its ordnance capability. It must be because of its air-to-air capability only.