There’s a few 240s in Ontario already running this setup, pretty sure with a winters quickchange. Same as what most super late and pro late oval track cars run.
any final drive you want, i’ve seen gears put in these diffs from a 3.20 ish to a 6.90 and it takes about 15 minutes to do
gear options and time (hence the name quick change) is the main reason these exist.
its a normal differential flipped around, and the driveshaft goes under it and into a gearbox, then into the back of the diff, all you do is pull the rear cover off and pull your two gears off, slide other ones on with a different ratio and your back at er’
I’m guessing that since pro drifters must see a lot of different tracks they can switch out ratios that best suit that track for their powerband or whatever.