your rebel has 3.92 gearing (i assume all Rebels do) you will be fine.
however, you're gonna cut your frame to fit 6" kits that doesn't add additional clearances just to run 37s?
no additional suspension travel than regular 3" kits, no additional ground clearance than regular 3" kits, no returning to stock or going back with those 4"+ kits, no skid plates with 4"+ kits.
i've seen people local to me fit 37s with 3" kits. granted, a lot of trimming and possible removal of fender liner is required but at least you're not putting yourself down a path of no return.
edit: i have done it on customer's truck and it was... terrible. Ride quality is not good, extra work required, 100% wouldn't recommend. Yes, we charged more and made more, but I much rather do a 3" and charge less for a better ride truck.
