Remasters don't affect the levels of the instruments or vocals of the original. You need a remix for that. Having said that, adjusting the EQ and compression levels, which is pretty much what a remaster is, can enhance some elements slightly which can have an affect on how they sit within the audio spectrum. Its very subtle though and very subjective and usually defined with very nebulous phrases i.e "a little more air around the cymbals" or "slightly more authority in the attack" or similar.
Check out the Steve Hoffman audio forums for further examples- and there are thousands- of audiophile nonsense.