Last year i wanted to go the other way, from ZRH to FRA. I could have rented a 3er for about 500 Eur for 1 week with the one way rental. I was renting from SIXT however as I've read good things on this forum about them.

Anyway, I did not book in time (more than 24hrs in advance) and I watched the rate go way up, so I ended up taking the train to Germany and renting in Germany. I was upgraded from the 3er to an A6 with Nav. Nav was handy, A6 was nice, but I would have rather been driving the Bimmer around on the Autobahn. A6 was FWD and could barely make 240kph!