I have to admit that I have a slight addiction to power. The Renntech kit is my list of things to do, but based on your description it's moved up a notch. I know someone that had a car custom built by Renntech and I have to say their quality, service and a support is outstanding. They are also one of the top Mercedes tuners and have a close relationship with the factory especially since the founder is a former AMG employee.

For peace of mind and not wanting to risk damaging my motor, I would spend the extra money and go with a trusted brand like Renntech.

Based on the reading I've done, the numbers seem to be around 400 HP after the kit. I would really love to see dyno figures from a SRT-6 to back this up and not from an SLK 32.

I have a official Renntech tuner about a block from my office. Once I get my SRT I'll bring it by for a "consultation" and let everyone know what they say.

Saying that the difference is going from a non-SRT to an SRT with this upgrade says a lot!