i've seen a mopar e-cutout up close and personal... actually uninstalled one. they are loud when open and provide little to no difference in sound when closed. I know that an e-cutout on a SRT-4 sounded like a dump truck when open and had been known to shoot a flame or two with a wide open throttle shift (though that would be a minor issue in the SRT-6 seeing as it is automatic). It definately turns heads, and let people know they need to get out of the fast lane on the highway. However, there are two issues that I have seen. One: you cannot leave it open when cruising, at least in the SRT-4, because if you did you would throw a code - no fun. Two: There was a small issue with the motor actually sticking and not allwoing it to open/close. This could most likely be resolved with a cleaning and greasing once or twice a year. Just thought I would give you the heads up about that though.

As for the "50% open" I haven't heard anything like that. I think that it would probably work better fully open because of the reduction in backpressure that it provides and thus more HP. But I can't say for sure.

My $.02 plus.