BattV issue - alternator?

Are the problems shown below indicative of a failing alt (or Voltage regulator, but I believe it is internal).
The car will actually run rough at idle with the headlights on at times. Turn them off, and it idles OK again.

Check all the battery connections first. Make sure they are all clean and tight. Look for corrosion inside the connectors. And by inside, I mean where the wire clamps to or enters the post connectors. Also, check the grounds where they attach to the engine and body.

With tiny noise spikes, I'd try a noise filter before replacing the voltage regulator.

Will check grounds, Richard.

Matt, What about the drops down below 8v? Also, what type of noise filter do I need?

Dude, its a Fiat there are all sorts of grounding issues on them. Start at the front of the car and work backwards and clean every single connection and ground "bloom" including the battery cables. Make sure you're getting bare metal connection to bare metal. Use electrical connection grease to cover the bare metal to reduce the chance of rust forming.

If you haven't done the wiring modifications where you add relays for the headlights, wipers and ignition switch, do it (look up brown-wire mod on the xwebforum) that will help stabilize the common points of voltage drop in the electrical system of your Fiat.

From there you may find that a GM alternator conversion might help if you still have voltage spikes/sags (the GM alt is typically cheaper and more common than the Fiat alt)

Good luck and let us know if you still have problems.

The reason I don't think it is the regulator is that they are not sustained drops but single data points. I would check the grounds like the others have mentioned, but it wouldn't hurt to put a cheap stereo noise filter (I bought mine for around $10 at Autozone IIRC) in line with the 12 volt power wire, too.