Tire howl - for me, I can always tell when my tires have between 6,000 - 6,500 miles on them because they start to howl. Yours are probably doing it a little earlier because of riding style, tire maintenance, or road conditions. For me, once they start howling, they'll stay about the same until they get replaced.

Idle - any change in your RPMs when pulling in or letting out the clutch while in 'N' during warm-up ???