Just installed Curt 31449 on my April 2019 SR+. None of the bumper re-installations issues. The advice on re-insallation help a ton. Started in the middle underneath then worked both sides separately.
I did have a HELL of a time trying to install the crash bar. I followed the standard instructions to install the hitch to the car then install the crash bar but the bolts would not line up with the outer crash bar holes so I could tighten the middle and lower bolts due to them not flush with access holes. I worked it 2 hours. on the car and got real fed up. Took the hitch off the car and after some real effort I just managed to get it on and torque it to spec. Then installed the tow hitch with mounted crash bar to the car.
I did not have the access panel but I did have the tow wiring which I routed down to the hitch for future consideration. Cancellation of my model Y order after 2 months forced my hand to install a tow hitch to my Model 3 for my 75 pound Voltbike.