A couple of things.... Rhino is correct, X-90's did NOT come with the 5.12 gears They are 4.?? stock so a factory 5 speed Kick R&P will help you out and they are easy to come by.
Second, (I dont know if this was covered) The T-Case reduction is an AWESOME addition to any trail 4x4 BUT the Kick/X-90/Tracker reductions leave high range stock, there will be no on road benefit/rediction, so done be expecting it.
And Last (yea, I know, more than a couple)
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, there was a company (one of our sponsors) that was coming out with a in line reduction about a year or so ago. I can not remember who or what it was called, but one hell of an idea.... Hopefully someone else can jump in here and remind me who/what it was.
Zig