Re stability, It has been over 2 years and it is still there, there is very little wobble if clamped tight.
Re the QC3.0, I can't say, I use the lead that came with it, plugged into my F.M. converter. Running the Sat Nav with screen on and using the phone as a jukebox, after a 3 hour run it's still at 100% charge. (I've used it with Pixel3 and Pixel 5).