How to check whether the car is straight and true

[tcoradeschi]

I’d think you could get a rough idea by picking a couple of locations on the underbody itself, one set front and one set rear. The diagonal measurement from left front to right rear should equal the measurement from right front to left rear.

Alternatively, and no idea what it might cost, a body repair shop should have the skills and equipment to do that same sort of thing, but much more accurately.