As far as I know there are no differences on audio quality on any Radiohead CD,there are also no SACD's as yet.
The vinyl issue has been covered above.
Radiohead are a very collectable band and the band themselves seem to take their packaging very seriously.
As a result there a myriad of different versions of albums,singles,limited editions,promo's etc. however whilst there is differences on the packaging side there are no audio differences on the actual albums ( some singles do have extended versions,live versions and remixes but these are extra's) as far as I know.
There was an internet rumour that Kid A had been released in varying mixes with no way to identify them on the CD but I believe this turned out to be untrue.