I'm not entirely certain, but I believe that they've been transitioning to using as many ASP parts when building new Elites as possible now. One member confirmed with CS that the Epoch is now being made with ASP, with the switches in the choke rather than the body like it used to be. So the majority should be compatible with ASP for swapping out bits here and there. I can confirm with my Vanquish that at least the pommel threading matches ASP.
As far as price goes, ASP tends to come in below the Elites, and often by a fair margin. You'll find a few instances where an Elite saber is cheaper than its ASP verson, simply due to how some of the ASP parts are priced (such as the $90 Sorcerer emitter, $80 Vengeance body, and $60 Graflex switch).