Reshimming a 8.8 LS to make it lock up?

Anybody done this? I met a guy on the trail that was running an 8.8 limited slip and he said he added more shims to the limited slip to make the 8.8 lock up. Never saw it in action but he was running trails that would need a rear locker.Probably not ideal, just thought it sounded like a cheap way to get more traction. Anybody have any info good or bad.

You add more friction disks behind the side gears. My personal opinion is it's a pain in the ass and not worth the time. You still have to pull the carrier and then deal with the extra preload while putting the spiders back in. I figure if I'm tearing something down that far, might as well put something worth while back in.