Man, I'm so glad I found this shop. Took my s2000 to 2 different shops to find out what the mystery grinding/knocking sound was. Both installed parts without fixing the problem and tried to convince me it was my timing chain which would have been over a $1,000 fix. The guys did the diagnoses right in front of me and I was able to clearly see it was just the alternator bearings. These guys figured out the problem in less than 30 seconds. I am a very happy customer and will definitely be a regular to keep my car in top shape! Thanks for the honesty, guys; I really appreciate it!