Damn, I LOVE this track!
Honestly, I wouldn't change the vocals at all. They sit smoothly and subtly for the first minute, right along with the feel of the track. And I like how they're solitary, without the falsetto.
The only recommendation I would make would be to redo the overdriven guitar after around 2:30, with a sloppier, more dynamic performance. It's good as is, but disappears a bit because it's too nice (in my opinion).
Anyway, i'm going to listen to it again right now before I move on to another song.