Just got it so can't give a honest review yet. Heading to Hatfield and McCoy next month for 5 days so I'll learn a lot about it down there.
The new Rmax4 extended is not a stretched version of the original 4 seat. It's the Rmax2 that they based it on. The engine is now in the back and can be accessed when the bed is tilted, 30" squared stance on bead lock rims, upgraded shock setup, full rear doors with 8" more leg room, new MTX audio system built into a much improved Adventure Pro, steering assist adjustment (automatic increased assist when in diff lock) and finally a turf mode.