Tally TransAm

iTrader: (17)

thinking of getting a rear end shortly

question: what is pretty much the best street/strip diff for either a 12 bolt or 9". car is a daily driver making about 420-430 (hopefully) thats sees track time about 1-2 times per month

spool: not until i get a different daily
locker: heard they are noisy, and lock and unlock during shifting in daily driving
posi's: eaton, auburn, trac-loc, etc

i want something that will still allow daily driving but i dont have to worry about on a 6k dump at the track

any ideas. would like input for both the 9" and 12 bolt since i havent decided which one i want.

thanks