Did you get the artist's permission for posting those on the web like that?
Also, why not retrack the vocals if they are so out of tune.
I listened to the tune and you should definitely work the hi-hat and snare a lot more.
Just constructive advice.
Also, the guitars sound a little flat (sounds like it lacks some high-end presence to sound natural) and there is a weird resonance on some of the bass notes. Maybe put some more compression on the bass ?
Maybe also push the drums a little more upfront. Thye seem to vanish in the back.
All IMHO, of course.
As far as the vocals are concerned, they don't seem "THAT" out of tune to me. Of course, the guy doesn't have that great of a voice (IMHO) but it has it's own style that fits the band quite well. At the end when there are back vocals, it seems to be a little more "off".
I don't have autotune so I can't help with that, but I still suggest you retrack the vocal parts and ask the guy to sing to his full potential. Autotune will only get you partly there.
