I am somewhat concerned that you have been distributing all this open source software without access to the source code. Remember rockbox is GPLv2 (and uses tons of open source code from other projects like FAAD). I realize it can be difficult to immediately provide source code for every single binary you make, but you have been putting up multiple versions, a website, etc so now would be a good time to provide source as well.
In my experience, ports that are not subject to regular code review tend to be quite painful to merge, or in some cases end up abandoned. I strongly encourage you get more people looking at your code before you spend too much time on it, otherwise you may find that it's more work than it should be to get your port merged into the main git tree.
It changes the sampling rate of the playback engine, at least assuming the hardware and drivers support it.