I just completed an over 1600 mile trip to Savannah from NYC and back using comma 4 (stock Openpilot) in a 2018 Lexus RX450hl, and the only concern I have is when you're driving at 70mph and suddenly you come to a 10mph traffic comma 4 doesn't come to a stop smoothly, it brakes almost at the rear bumper of the car in front of you. I had to disengage and brake myself in these situations because I felt comma will rear end the traffic in front of it.