Well sadly the sound engine is so basic that the merlin engine is coded for every aircraft at the moment. thats how bad it is. also there are no and i mean no atmospheric sound features in the game at all, they will have to be coded into the sound engine.

Also would be nice to have the sound coded fully instead of half finished. Looking through those files it will take someone who knows how this game was written to create new sound sets in emds and prs's etc etc. Ie a dev.
I dont know what functionality people think is coming with the SDK and what use the SDK will be with steam, but the SDK is not ment to change hard code, just expand on it.