I made slits ... the rear seat is actually out of the rig (I don't wheel with it in), so just not "tucked in". I also punched holes for the "fold down" pulls. No aftermarket cover is going be a glive fit (unless you have major $$$$).
This aint a re-upulsture ... it's seatcovers. They are TOUGH tho, and yet don't look like total azz.
In my 2dr, I've run these for a couple of years (and ALWAYS with my dog).
My dog is an 80lb longhair german shepherd that likes to play in mud puddles. She also likes to "load up" via the front door. Her nails have never torn the front seat covers in the 2dr, and with some scotchguard, the water/mud is easy to sluff away. (If you have wheeled with a dog, you would "understand" why this is important).