Racing Chip
The CL500 has a naturally aspirated engine. It's hard to do software tuning on those kinds of cars, most of the gain you get is feeling, rather than dyno-provable results.
IMO, you're better off either making the jump to a forced induction AMG or V12, or investing in adding a super/turbo-charger to your current car.
If you're still interested in chips though, take a look at RENNtech, Powerchip, and Kleemann. There are plenty of sponsors on the forum that well even more products, just make sure you know what to expect







