Getting through Munich airport
 

Can anyone give me a roundabout idea of how long it would take to get through Munich's airport upon arrival? Are the passport lines typically long? We are US citizens and will be arriving nonstop into Munich in May with carry-ons only. I've been to MUC airport several times but always to fly out. Our flight arrives at 7:00 am. We will be taking the train to Munich Ost and then onto Freilassing, where we will pick up our rental car (our final destination is Berchtesgaden). I'm trying to get an idea of what time we should schedule the car rental pick-up. It will take roughly 2 hours (according to Bahn.de) to get between the two. There is a train that leaves MUC at 8:23, arriving in Freilassing at 10:33. Is that too ambitious? I realize the pick-up time doesn't have to be exact however I would like a rough estimate.