There's plenty of available info on oem vlsd's and super hicas via searching the site.
That said, there are ways (through driving, checking your diff carrier, search for more that's all I thought of right away...etc.) to check and see if you have a vlsd. I would just turn the car in a tight circle in first gear, then give full throttle and see if your car spins one or both wheels. You'll know it's both if you end up facing the other direction rather quickly but you should be able to feel the difference. It's a fun way to check.
Super hicas as said, is nissan's 4 wheel steering system. This is ahrder to 'fel' on the car but very easy to see by hopping under the rear axle and looking for a hydraulic pump right behind the differential carrier. There will be tie rods going to the rear wheels to move them left or right. If you have hicas you'll see the hydraulic pump and tie rods....google search for images of it if you aren't sure :

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Neat fact: Super Hicas= Super HIgh-Capacity Actively Controlled Suspension