Sorry it took me so long to reply, I did not notice your post. So, you dumped a lot of cash into your SL55? I know a few others that have done the same but here's the details on what you'll be facing if we meet: 650HP & 790LBS of torque at 1,800RPMS. You may beat me off the line based on sheer weight and some slight tubo lag, but I can almost assure you that I'll be screaming past you within a split second. Short of having your engine completely replaced, no amount of street legal alteration to the SL55 will help. This is why I purchased the SL600. I feel that it is simply the best value in the SL line due to it's upgradability. The RENNtech SL600 with the sport package is just as good looking as the SL65 but "faster" and smoother riding. But the best part is that you can fully load your RENNtech SL600 with every option available and it's still way less than even the base model SL65. The difference could actually be 30 to 50 thousand dollars less. As for the SL55, well I do like it but it just cannot be substantially upgraded without spending huge money and the end result is still not satisfactory preformance for me. But don't get me wrong, I do love SL55's too. There is someting to be said about that quick and light feeling the car seems to have. It is really fun to drive because it just feels so nimble. The down side of the V12's is that the are heavy in the front end and so you trade the sporty nimble feel for the luxury cruiser feel. But again, add the RENNtech package and you can have both, sport and luxury. Any way, if you need to know, I live in the Saratoga area of the Capital Region of NYS. Perhaps we'll meet and we may drive each other's cars. Perhaps I will be surprised as "you" pass me? You never know!!