Alot of the V6's now are supercharged or turbo charged. If you are getting a car without a warranty, you can buy a chip and gain some of that power.
Do you have your own garage or a driveway? Some of the cost of ownership can be decreased by alot if you start working on it yourself. Just start with oil changes, which most time is quicker than the time to dealer. After that you can add stuff you are comfortable doing, alot of little things are sometime real easy to change but the cost of dealer parts and labor just drives up cost of ownership. Finding tutorials and the right suppliers to get parts makes alot cheaper.
While I have never been in one, I've heard good things about the CL550 and the S-class coupes, which they decided to change the name to. They are fast but not too fast, plus a luxurious interior and a real comfortable ride.