Gas mileage will be 17 - 26 city - freeway depending how one drives. But
that's not the important cost to be considered; the repair cost(s) on
these cars is high so many owners become DIY maintainers and, in some
cases, mechanics. Parts are widely available for DIY so it's up to you.

As to a CE vs. sedan: same power train but shorter body so some CE parts
are specialized and that means more $ for them, especially at a dealer.
A sedan is the better over all package, though not as eye appealing.

500SL 2005   Highway 8.3 liters at 110 Km/h on cruse control