Warp records is now selling digital downloads of Autechre also in the losless flac format. The quality is supposed to be the same as a CD (as far as I know), but a flac file only needs half the memory a regular wav file needs. To listen to flac files, usualy a plug-in for the media player of your choice is needed, which is available for every of them.

Autechre on the topic of mp3:

"I think it's very important to listen to it as one piece, and it's very important to listen to it on CD -- there's such quick transience between a lot of the sounds, they don't come through very well on MP3"

Found via: milieu.alexyoung.org