Got everything installed on Monday between sleet and hail showers, but will need to reopen the car up as I'm getting a wee bit of alternator whine, which wasn't there in my old Impreza, and for some reason the headlight sense doesn't appear to work, so no dimming. I think the Illumination is on pin one of the Subaru plug for the stereo, but I'll need to go and check.

I've had a good look through previous threads but found no definitive cure for alternator whine, so I'll try:

rerouting the empeg-amp cables
using a different ground - currently bolted under the driver's seat next to the amp

Any other ideas gratefully received.