RE: DBC mods.
Yes Remember it is this battery that is now driving the Benedini sound. Not sure how long you get with a small receiver battery pack. I know you can drive one of those amplified ipod speakers all day long on on three AAA batteries, so I am assuming this battery pack will drive the Benedini for as long as the tank battery lasted.
I have a 7.2 Volt 600 ma pack out of the WSN Halftrack I am going to use when I am going to get real serious about a tank battle. Again in most cases this isn't an issue, but if for some reason you are experiencing anything flaky with any of the DBC line, consider this as a possible fix.
One other fix might be just the gauge of wire a guy uses between the battery and the RX18. Perhaps less resistance in the wire would be enough to prevent the problem? Maybe that is why this experience isn't universal. That would even be an easier fix. Use the same guage as the wire on the charging plug. Maybe the current is choked in the small wire, and when there is an excessive amp draw you just can't supply enough power to everything that needs it. The DBC with its digital signaling is more sensitve to this. This might also explain why the Tamiya has the mystery reset as well. Same kind of thing happening. Just a thought.