For posi the auburn and eaton are the way to go, they are proven performers. The eaton may have a tad advantage over the auburn but you'll pay for it. The reason is, the eaton is rebuildable, but i say who cares, my auburn will last long enuff for me. The lockers and spools are probably too hard on the street. You seem like you drive yours all the time, so that shouldn't be an option. The eaton and auburn are very easy on the street and hook up very nice at the track. I don't get a any spin when i take off, at least i don't hear any, when i'm at the track with slicks.
With the auburn in, i don't even notice i have it until i get on it. At low and high speeds it will grab. if i just barely turn my back wheels during a brake stand, they will both turn. I like it a lot.
now i just need some good street tires so that i can hook up on the street, i can still spin those cheap tires pretty good.


goodluck,

allen