Essen is 442 kms from Bamberg. It's about a 3.5 hour drive. I plan on driving up the night before. Google maps says its a four hour drive. I think the last time I drove there it took me three hours, though. Its not a bad drive up the A7. But IF you go the other way up o the A3 that is a PITA - with all the construction and traffic.
The Essen Motor Show is the German version of SEMA. It is an interesting event. Its been a few years since I have gone - so I will go this year. I really much prefer the Techno Classica Show. That is in the spring time (April or March) I think.