We are thinking about buying a new Toyota with parking sensors. How effective are they? How close can you get to a wall with them?

We want to get a Sienna but our garage is pretty tight. If we can park very close to the wall (driving forward into the garage) that would help a lot. We have white drywall if that makes any difference. I was hoping we could get within 6 inches of the wall. The dealer doesn't have any XLE Limited models with that feature so we can't test it out.

What is everyone's experience with them? Thanks in advance.