Finally, I have an update. A couple weeks ago, I went to Nate @ S-squared, and he installed an anti-lift kit for me. Since then, I've had absolutely no clunking, and I've put about 1500 miles of hard driving on the car since then.
I also got an alignment right after the kit was installed. The car is feeling good now... one day my AccessPort is going to show up to take it up another notch.