D-25 and D-40 acceleration are the same, but you are right if the pilot knows what he's doing. In fact, both jugs equal or nearly close to equal on all aspects of performance except the D-40 slightly better climb rate with WEP, D-25 slightly better on turn raids with no flaps and D-40 a hair better on turn raids with flaps.
Going back to acceleration. When I say I accelerated better than the D-40 that may because my load out. I never used %100 or %75 fuel. I also used the smaller load of the six gun package.
D40 has more WEP horsepower with the same airframe, with 2600 HP available versus the 2200 HP on the D-25. In a drag race at the same weight, it has to accelerate better. With more power, its also going to have better sustained turn performance with WEP (note, not necessarily reflected in the turn radius), because it has more power available with the same power required. The reason the D-40 has better climb rate is because of its higher power with WEP. The D-25 has the same power as the D-11, but has the high-activity propeller (aka "paddleblade), which is reflected in the better climb rate. It has a slower speed because of the wing pylons.
When comparing the D-25 and D-40, make sure you use the same load out, because they should have basically the same weight. Personally, I never felt the 6-gun package was worth the loss in firepower. But, if you do use it, remember that the only weight advantage is by using the 6-gun, light ammo load, as the 6-gun, heavy ammo load weighs more than the 8-gun, light ammo load. For the D11, I always used the 8-gun light load, and 100% internal, with a drop. Legs are too short to take off with less, IMO. For the later model D's, I usually went with 75% internal and no drop. For the N, it was always 50% internal, center drop.
