DCS World and 32bit Vista OS?

Yes,  

I didn't want to go further into details, but indeed there are, at least for me, so many many difference ( for better ) between the best p51d add-ons for FSX and what I get with DCS's p51d, that one of the reasons I trashed FSX for good was that I finally found a flight simulator that, not being the type of flying I like to make ( combat ) can nonetheless be used for civil flight too, flying in formation, trainning aerobatics, etc...

It's fluid and has acceptable graphics that will most probably get even better when EDGE becomes available anytime soon. But above all, the fidelity and detail of it's flight dynamics is so good and ahead of any other sim, including another combat flightsim I now use and is also very good - IL2 BOS - that I could never return beck to FSX or X-Plane 10. Actually I am using XP10 as a visual scenery generator for Aerowinx PSX :-)

Simply set your best FSX p51d on a whigh power climb, at high AoA, and  start cycling your throttle... Admire the stability of you aircraft, as if you didn't have a prop ahead of you, and a powerful engine moving it, with all of it's torque effects.

Go vertical, like in a hamerhead, and near the top apply full cross-controls... Observe....

Simply takeoff and land the p51d on both sims, making sure ( as Rodd pointed out ) that you are not using any takeoff or rudder assist, and are using the "real" model, not the "game mode" in DCS!

It's sooooo different...

Anyways, some author's have been able to take FSX to the limits of what it's FDM allows, and A2A was certainly one of them - a reference!