Now this just nerfs the Driver to an extreme especially since as far as I can tell once you take a move like Good in a Clinch it replaces your ability to use the previous stat. Maybe you can still choice the other way.  It doesn't help that any other playbook can take that move and suddenly be rolling +5 or +6 as well.

"...if you do something under fire add your car's power to the roll."

"Drivers get to add their cars’ stats to most of their basic moves
— notably excluding the ones that call for a roll+sharp or a
roll+weird — but not to any of their special moves."

Using this wording, sure you could say using good a clinch excludes you from adding your car's power to the roll. I would argue though that the point of A no shit driver is to make you better at the basic moves it specifically lists. Otherwise it actually makes less sense to take good in a clinch since you are going to be behind the wheel most of the time anyway due being a driver and all.

My other argument is that Good in a clinch may be a move but you aren't making that move when you are doing something under fire. You are still using do something under fire but it has been enhanced by the Good in a clinch move.

Hey maybe I'm wrong but you don't start with +3 in any stats or get +3 in any of the vehicle profiles by default so you as the MC can keep it from getting out of hand to start but as the characters grow what's wrong with them making it every time? Unless they get 10+ they are still going to be paying for the roll in some way or another.

tldr

Good a in clinch shouldn't stop you from adding car's power to a do something underfire roll as a driver.