[elhigh]

That clunking might be a worn bushing in your suspension. If it does it only when the suspension moves - like you described - but not when you're in a steady state with nothing else going on like coasting on a straight stretch, then get 'er up on the stands and take a peek around. Or wheel on over to a suspension shop and while you're getting a good alignment, have 'em check that out too. They'll be equipped to set you straight toot sweet, and if your wheels are out of line that's some easy economy gains right there.