Yes, lean means too much air or not enough fuel, and bikes actually tend to run richer at high altitude (less oxygen in the air) but frankly I think that half the pinging problem is in the ignition timing & that you can't really adjust AFAIK.
If your bike is pinging now, then it may ping a bit worse if you mod the intake and do the goat belly as well, but doing both of these things will definately make a little more noise. Maybe not enough to get you busted, but much depends on how you work the throttle.
Bear in mind that the resistor mod isn't as precise as a TFI and that's not as precise as a properly tuned PC-III, so considering your altitude a PC-III might be the best choice, if there's a good dynotuner in your area.