Changed to DX9 and it resolved SOME of the problems, but now I'm getting all the instability related to DX9.

This is definitely a problem related to whatever new sound stuff is with the game, hopefully they either fix it or remove it soon.

I'm not losing any FPS at all when it happens, oddly enough. I also know my GPU is not even close to maxed out. The only -possible- thing on my end might be my CPU but that's highly unlikely as prior to the expansion there wasn't even the slightest hint of problems and other games are just fine.