after being KO'd by Serra, i don't think GSP will play the standup game with many more of his opponents. i think he'll have a little trouble keeping Alves down, but i can see him getting repeated takedowns. GSP would be wise to get Alves down though. If GSP got TKO'd by a natural LW in Serra, i expect Alves can do the same. Not to mention, GSP would be wise to get the fight to the ground so he doesn't take any of Alves' murderous leg kicks.
i still think GSP would win a decision victory, but it wouldn't be a cakewalk like his fights with Hughes or the 2nd victory against Serra.