We've all heard about the Eaton E-locker, a fully open diff that locks electrically (ie without an air line connection or compressor) to become a full locker. We may also have heard of the Eaton True-Trac, a torsen style LSD that never wears clutch packs or goes out of adjustment. Eaton, however, have not made these in Suzuki-sized applications, instead concentrating on mainly US-market domestic 4x4s. https://www.eaton.com/us/en-us/products ... tials.html
An Australian company, Harrop Engineering, have taken Eaton centres and machined new housings to use in a wider range of vehicles (ie Japanese + UK), but there is still only one Suzuki application, the larger Vitara rear diff: https://www.harrop.com.au/shop/4x4-perf ... itara-rear.
Meanwhile, in Japan, an engineering company has taken Harrop's lead and created a unique locker that is not covered by either Eaton or Harrop, and it's for the 26 spline small 10-bolt diff in the Jimny!!
Provided you also find a 10-bolt R&P (4.09 or 4.3 ratios), you can fit this locker to a Sierra! . But what is really cool is that this locker COMBINES the Tru-Trac LSD centre WITH an E-locker! 
.Pricing is still a bit vague with the Jap Yen exchange rate being a bit poor, but with these lockers priced at 108,000JPY, they work out something like AU$1500, plus GST when you sneak it through customs. Sounds a lot, but it probably going to be just under the price for a Harrop e-locker for a Vit rear, but with the added benefit of an LSD!
