A little research should have put your Chrysler prejudice to rest. The SRT6 was a quick-n-cheap development effort using the existing Mercedes R170 chassis and existing hand built AMG engine and transmission along with Mercedes brakes, diff, and suspension design. Most of the interior was stolen from the SLK32 as well. And the car was built by Karmann in Germany under contract to Daimler/Chrysler.

As far as I can tell, the only things Chrysler had its hands on were.....

• A fixed roof which reduced complexity and probably cost while removing weight and adding rigidity.
• The exterior sheet metal where I think Eric Stoddard and crew knocked it out of the park.
• The wheels, where again I think Chrysler made a stylish choice for Eric Stoddard's overall design even if they are a monumental PITB to clean and wax.
• The suspension tuning where the crew at SRT tuned the car much more to my liking than its SLK32AMG ancestor.
• Some minor interior bits and styling like the silver center stack. Which by the way is only thing I'm not really fond of. I think some selective use of real fake wood would have dressed it up and been more in keeping with the art deco exterior styling.
• A huge rear wing that I've learned to like as part of the overall package.

So, Chrysler had much more to do with style than function. The car is basically German hand me downs through and through and screwed together by Germans. And it shows in the fit-n-finish when compared to 04/05 era Chryslers designed and built in North America. For whatever reason, Daimler/Chrysler didn't go out of its way to explain what the SRT6 was. I've assumed like you there was internal prejudice against the Chrysler brand and Mercedes didn't want to advertise the genetic link while Chrysler didn't want to disclose the fact they were rolling out "new" Mercedes hand me downs. BTW, they were doing the same thing with the Pacifica. That car stole the E-Class suspension design and the interior design was heavily influenced by Daimler. That's the reason the Pacifica interior looks waaaay better than anything else Chrysler was making in North America in the 04/05 timeframe.