Been there...all the brands are set up together, and there's plenty of room. BUT, most of them were picked of the really good stuff before they go in the 'pick-em' pile. The interiors are usually complete, and you might find a trick overhead console, of trim that will work on your ride. Overall, it's worth the visit.
I haven't been on their all-you-can-carry days, but I'd imagine it would be crowded.
Stiletto heals are NOT recommended. Steel toes are the plan, and you will get dirty...but, that's 1/2 the fun.