I had this exact same problem. My car drove just fine but as soon as I pushed the clutch to the floor I could hear the noise. I got to were I could find that sweet spot in the clutch pedal where the noise would stop. I pulled my trans to install a Monster level 1 clutch, new slave, new pilot bearing, and Tick master cylinder. Anyhow, once I got it apart I found that my throw out bearing was completely trashed along with my pilot bearing. As a matter or fact I have a picture of what my pilot bearing looked like. The needle bearings had turned to a black powder dust behind the bearing next to the crank plug. It actually did some minor damage to my input shaft. I'll post a picture up here for you of my pilot bearing and what it did to my input shaft. I would stop driving it if I were you.