the SRT6 is a 5.3 or 5.4 second car, and the Limited 6 speed is a 6.1 to 6.4 second car. I'm not sure where you get those figures for the SLK32 or if they are legit, being the SLK32 has a time of 4.5s and puts out about 350 hp to the crank compared to the SRT6 which is 330hp at the crank. It's kinda hard to believe that 20 more hp can bump a cars 0-60 time that much.