We arrived early due to having to disembark our cruise earlier than expected. As such, our car was not ready. We wanted to upgrade but the only car that met our needs and was available was an A6 diesel wagon. Priced quite a bit more than what we wanted to upgrade to. As we were short on time with the need to get our luggage from the cruise boat, we took the A6. It was a great car to tour Germany with and any faults with the car lie with Audi and not Sixt. What I did not like was the lack of any explanation of the diesel car. I knew it would need Ad-blu at some point but the manual was only in German and the iPhone translation had limited usefulness. Turned out, it was low on the Ad-Blu fluid from around 10 miles from pick up. I wondered why the mileage to go display had a red outline when the display clearly showed 700+ Km to go. After a couple days, despite there not being a symbol to add fluid showing I put in 5L of Ad-Blu. The red outline finally went away and I was able to relax for the rest of the trip. Beyond that issue, the young woman at the counter when I picked up the car only put down on the contract that I had only one day of rental, despite that I had booked the original reservation for 8 days. This caused some consternation while Sixt worked out the details over the weekend and I finally got an email on Monday with new details. Apparently 1500€ more than I’d already paid…still not sure but I think that’s close. So instead of a $700 rental it’s more like $2500 maybe more. Turn in was easy and zero drama which was quite nice after the initial problems.