This is my first post. Just bought a 2003 Z06 (Electron blue) with 6,900 miles from a local dealer for $39,000 (felt like it was a good buy?). I took it out today for for a shakedown run on my favorite twisties and after about an hour drive or so, if I'm at a light in neutral, I hear a rattle noise coming from under the car about 3/4 ways back. If I put in the clutch pedal, the noise goes away. I'm thinking throwout bearing? It only does it after a long ride. The engine also idles a little rough, assume it is normal because of the cam? I must admit I'm a little disappointed with the power, thought 405 hp was rear wheel horsepower...is this at the flywheel?