Hi - couple quick questions, and any feedback at all is helpful.

I've never rented from Sixt, but looking at a one-way Zagreb to Dubrovnik (8 day rental).

1) Should I pick up the car at their city location or the airport? Any real differences? I'm only planning on spending two nights in Zagreb, so I can either get the car when I land and pay two more days, or swing back to the airport to grab it there if I'll get better service than their location in the city (that seems to be in a hotel).

2) I'm a National Executive Elite - would getting a status match give me any real benefits (upgrades, better service?).

3) Anything I should watch out for?

4) I'm inclined to shoot for a slightly better car than a VW Polo - from a bit of reading, it seems like involuntary downgrades are common, is it even worth it to try to reserve a Mercedes GLA or better?

Thanks in advance.