linux, I've driven both cars (as well as nearly everything in both manufacturers' product lines) I was recently invited to a MB test drive session here at El Toro, where they set up handling and performance courses for quite a few of the cars in their product line, including the SL55 AMG and the SLK350. They had a SL65 there, but didn't let us drive it on the course
I think the SLK350 is a pretty nice car, and it does have a pretty decent punch to it, and its handling is improved over the SLK-230 but it's not as good a driver's car than either the convertible or coupe M3s, IMO. BTW, I've driven a E46 M3 coupe at Buttonwillow before (when it first came out) so I have quite a bit of seat time in that particular car, it, along with the M5, were cars I considered when I bought my E55. I can see how it would appear to be a faster car, what you're feeling is the low rpm torque spike, but perception and reality are two different things. If you drove a LT1 based camaro/firebird, you'd feel a much stronger torque spike, accompanied with breaking the rear end loose upon a sharp application of throttle, and you'd think the car felt faster, but you wouldn't get much more than 14.2-14.3@100 or so out of it.