If I had to guess, the Baltimore ALMS race will be 2 hours; most definitely will not go beyond 2:45.
The Audi's were a thing to see (and NOT hear). They were so quiet that you could hold a conversation as they sped right by you 30' away. If you like Porches, BMWs, a few Corvettes in the GT classes and throw in the faster LMP classes, well you end up with a pretty interesting race.
I don't know how smooth they can get those streets in B'more, but they need to do something on a few of them. The pit is in a really odd location. They are putting it between Camden Yards and the warehouse from the looks of the map on their website. Theres virtually no sight lines from there. There's a few other odd things that don't look quite right and unless they are tearing out some traffic islands there are going to be a few narrow and tight turns.