Anybody had an ESP linked Hum through the BOSE?

[TonyFoo]

There's a bit of an electronic whine as the ESP starts to kill the fun which is not too bad as you can just turn the wretched thing off.

More annoying is the intermittent turbocharger sound that sounds like unsurpressed radio interference coming through the speakers, even with the volume turned down.

Have had Wayside Audi look at it but typically the damn thing disappeared when I took the technician out for a spin (white knuckles and all). They found nothing when reconnecting the TV (which they had kindly disconnected when it was in for a check on the phone hands-free) but the noise came back a couple of days later. Thought it might be a hot weather thing but it's cooled-down aplenty and it still hums.

Anybody got any ideas?