To clear your doubt about throttle response on Jlu, being an owner of one, i never felt this. i always use stick shift, not "D". mostly on 1st and 2nd gear, it conquers any tall dune like a champ. Jlu has better gear ratio than Jku (non rubicon models), that said you don't need any throttle response controller. instead you can get a good set of tires (not more than 33") for good traction and may be an axle back exhaust/cold air intake. i bolted my jeep with these.
@Rinelle Sanaani drives a complete stock jlu and it is an absolute monster.
Never underestimate a jeep !