Talk to the service manager, and request they TEST DRIVE it.
Edit: check tire balancing also.
Edit: check tire balancing also.
Sorry, I tried to add my signature and it didn't show up in original post.sounds like they went through it pretty good. Are you running stock so we can understand the possible issues. example toe in and caster angle and balancing. Balancing only if you've done nothing.
Caster if it's lifted and toe in if larger tires.
How much play do they have off of the lot, does anyone know or do they vary?