Spring RTS Engine

Are you going to change/improve the sounds? Will there be EAX3 support for example?

I believe everything above EAX2 requires special licensing from Creative, that being the reason why Nvidia among others only support that much for their integrated audio solutions. Think the same thing applies to developers.
Still there are other technologies almost as good too.

I'm guessing they are going to use the original sounds, though perhaps mods will provide new, better ones eventually.

Im thinking that in 1st person, there would have to be some new sounds

Yeah, like motion animation. That will have to wait though, until the new unit format with new script commands.