I am with Brian, I wouldn't bother locking a 7.5
Eaton/Detroit Locker has arguably the best reputation out there but, but keep in mind that the E-Locker is an "open" diff until it is activated to lock. So it is either fully locked or open.
Auburn Gear makes a limited slip/electronic locker for the 8.8 as well. It works as a limited slip until electronically activated to lock just like the E-Locker but with the full time limited slip.
The two are also similar in price if I remember correctly, with the Auburn being slightly cheaper.
'03 FX4 4.0 Stepside - 33" DuraTracs, DC-2s, JBA Headers, Custom Exhaust, AEM Intake, X-Cal2, Pulleys, Winch, 3" BL, Explorer leafs...
'99 4X4 Off Road 3.0 - SOLD
I just got out of the Army (7+ years), I'm in Minnesota, I just left Korea.