Wow. Aside from humorous comments from smartass old-timers, this is potentially a very misleading thread for new folks, in my opinion.
The (discontinued) MazdaComp LSD for 1.6s is a great unit and near-bulletproof in anything with Miata/RX-7 levels of power. I'll buy them for $375 ALL DAY LONG, feel free to email me if you have one on hand that you will sell for $375! I tell customers and friends to buy a Comp LSD unit (installed in a carrier) from folks they trust for $650 minimum!
My opinion, as I've told many people privately: A full 1.6 carrier with a MazdaComp LSD ready to go is worth as much as $950, if it has been "looked over" by a reputable builder, or you are buying it from someone you trust and they are giving you a 4-weekend "gentleman's warranty".
Any reliability issues with 1.6 diffs are due to the "undersized" ring and pinion gear and, to a much *larger* extent, BAD setups! These have nothing to do with the MazdaComp LSD itself - in fact, the MazdaComp LSD will normally survive multiple explosions of rings and pinions, because the ring and pinion "shrapnel" is large and the Comp LSD clearances are very small.
For every car and driver we have A-B test data on, the 1.6 diff (whether MazdaComp or Cusco) is absolutely significantly faster than the 1.8 Torsen diff - the issue is setting up the 1.6 ring and pinion to survive, which some builders (and probably all builders that don't specialize in SM) have yet to figure out. This is very old news, unless you don't know who Mike Backus or Jarrod Igou are ... I think those guys blew up 1.6 diffs every 1-2 weekends!
(Hint: Do NOT set up a used 1.6 diff per the factory service manual ... talk to a builder that caters to SM and knows what they are doing!)