guys, be careful, you are all exceeding the 75.000€ insurance limit with these car not just a bit. the s350 at sixt is already with extras close to 90.000.
SL350, CL500, S8 and so on are way above 100.000€.
which means you are risking 25.000 to 50.000€

yes, the white Audis S8 are more than beautiful, but... if the car is stolen or has total damage... you wont be renting cars for some time in the future

btw, sixt has 530xd (4wheeldrive), but quite rare.
many of the audi a6 are 2.7tdi. these do not have 4wheeldrive