Given a choice most autox guys seem to like the Torsen (Tru-Track) limited slip. There's a factor of availability, price, and personal preference involved.

I have seen a 68 Mustang that used a Detroit Locker in autocross. But I don't know if he can't use a Torsen due to rules or if it's a choice. He's the original owner and he's been running a Locker before they had Torsen's for a 9". So he's got years of fine tuning his setup with the Locker. He did say you have to get used to it.

Because of the tight turns on a autocross, some people have problems burning up clutch type limited slips.

We run a Detroit Locker on our Circle Track cars. The drivers do have to drive them different than running a spool. The drivers have to get off the gas differently coming into the turn to unlock it. Many times there are rules to keep the cost down for racers that don't allow Torsens or Lockers. So running a certain type might be a rules thing more than a choice thing.

Torsen's are the most expensive of the three types.