I have a 2016 3 pedal yxz with the gytr 70/30/15 gear reduction installed. the car has 1100 miles total 92 hours. Around 800 miles on the reduction kit. Looking to swap to a completely stock transmission with low miles/hours. Location: Eastern Kentucky.
There are lots of left over parts from that same conversion and I have seen them on eBay many times. You don't even need the original case as yours will clear the stock gears without issue. Probably get the gears you need pretty easily with some research and time on-line. That is the way I would be going to cheaply get back to OEM. The swap really isn't that hard. There are many videos to watch.... Good luck with however you proceed, but the last good used stock tranny I saw was around $3K.