The modifications are stated as follows:
Dyno-Comp Long Tube Headers
Dyno-Comp Mid-Pipes w/ X-Pipe
BMC High Flow Panel Air Filters
Dyno-Comp ECU Upgrade
Those parts are definitely good for something in the high 400 wheel range. It would be nice to see dyno runs from the headers only, then mid-pipes, and then tune to see how all the parts come together instead of just one result. To get an idea of tune only P31 C63 AMG M156 gains take a look at OE Tuning's result on a P31 car on a Dyno Dynamics: http://www.benzboost.com/content.php...-tuned-C63-AMG
Additionally, take a look at what shootout mode numbers on the Dyno Dynamics look like on a C63 AMG from Eurocharged here: http://www.benzboost.com/showthread....117#post181117
Now, this car is definitely making more power than stock but the correction factor is exaggerating those gains somewhat. Hopefully in the future Dyno-Comp will show multiple runs for the modifications so that the data is more useful. It would be nice to see the gains of the headers alone for example.