Need help to output full dolby true hd and dts hd

Hi. I currently have an asus xonar dx and a blu ray rom. I can play bluray movies on my pc with speakers logitech x-540. but what i have read is that, there is some protection that prohibits the delivery of true dolby truehd. it is said that the sound is downsampled to that of dolby digital somewhere i think is 48khz/16bit. i'd like to have a full 96khz/48bit sound to my x-540 since i don't own a receiver.

I'm thinking of getting an asus xonar hdav slim 1.3. is there some difference between the slim and the more expensive versions?deluxe?

and also, will the protection be gone when i'm using it even if i'm not bitstreaming the sound? or will it be the same, downsampled because it is output to analog (x-540)?

Thanks...