I hold a membership and visit the museum frequently. As Dave is noting above, the best time to visit is during one of the demo Saturdays. It's a pretty amazing experience to see and hear 1 of the 6 Shelby Daytona Coupes driving around the back lot. Check out the story on CSX2287, it's fascinating.(
https://en.m.wikipedia.org/wiki/Shelby_Daytona)
The best part is at the end of the demos when the audience is permitted to get up close and inspect the cars and chat with the museum staff and the good doctor himself.
Make this museum a must-see if you are ever in the Philadelphia area.