According to various SRT owners the S/C clutch engages somewhere between 2,500 and 3,500 RPM. Not sure if it varies or not. The only way I'd be able to say for sure is to put a tap on the line and monitor it during driving to see when it was activated. So, by putting it on a switch, you could turn it on only when you needed it (not sure what the performance impact would be). Another option would be to find out where the ECU gets it's RPM signal from and make a circuit to turn on the S/C above a set RPM via a relay. (Wish woody was here, he could explain it better than me).

So, the ECU does not have any control over the Auto-Stick? I find that hard to believe. If there is a separate Transmission Control Unit (I haven't looked at the wiring diagrams on this), then it still has to communicate with the ECU to get engine data to determine up and down shift points and limits. All modern electronically controlled automatic transmissions work in this fashion. Either you have a single ECU/TCU or two separate boxes, but there IS a computer system controlling that automatic transmission.