CLK's are great, but now you're talking about a coupe instead of a convertible.
I like both cars, but I guess you need to decide what you'd rather be driving.
If it were me, I'd always opt for the V8. Plus, you wouldn't feel embarrassed if a Lexus SC430 pulled up next to you.
I looked at SLK's, but man are they small. Sit in one and you'll see what I mean. I'm a pretty tall guy (6'1", 180 lbs.), though.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".