[DickB]

What you may be hearing is actually intake noise. The supercharger sucks a lot of air. If you notice it especially at a stop sign when you accelerate hard, you have relatively low background noise (wind and tires) and lots of blower action. Actually Mercedes did a pretty good job of quieting blower noise IMHO. I have a similar Eaton supercharger (aftermarket) on my Miata and it is loud. It really whines when you step on it. The first time I nailed it after the installation I thought I had broken something. After a while it becomes second nature, and many like me end up finding it appealing.