One more thought on the 4-6-8 cylinder question. A 4 cylinder may be straining its guts out to do what would be loafing for an 8. How long do you think the 4 is going to last at that output level? The lifespan of the 4 could be quite a bit less. My 560 has over 342k miles on it. I figure three things made it last this long:
Good maintenance by the two previous owners.
Plenty of reserve power so the engine was seldom stressed.
The two previous owners didn't have near the lead foot I have.
For city driving, I vote for a stick shift diesel!

342K miles! Good goin' :)

I dumped my '91 VW Gti for a bigger V8 powered car.

It was a nice little torquey motor for the city, but a buzz box on the interstate. Since my driving route has radically changed to hwy and interstate commuting, I figured we should make it an "all V8" family.

I love my C 230 K.
Power on demand ( you can surprise a lot of people with that little hair dryer under the hood ), and awesome fuel economy as an added bonus.
As an ex Mustang 5.0 owner, I am not easily impressed, but my little 230 K is starting to make an impression on me. ;)

The last time I had anything to do with a v8 was a 1972 Ford pick up truck and that was during the early/mid 70's. It's been mostly four cylinders since that time. I owned a 6 cylinder for awhile (1995 E320) and finally settled in with the five cylinder diesels:). If work were within 5 miles I would probably just ride the bicycle. I could easily get by just fine on the Yamaha Jog 50cc (50+ mpg) on a daily basis. The absolute most enjoyable commute I have ever had was an 11 mile, one way, commute to work on the Bianchi Eros - did that real regular for about 4 years:). The area where I live is suited for bicycle (weather/terrain wise) riding/commuting and it would be nice to have bicycle lanes but that is not the way they build things. I suspect that will change when gasoline is $3/gallon.