I purchased the upgraded ceramic bearing and belt kit for my Powerdyne Supercharger from 928 Motorsports and the bearing failed after only 3,000 miles. When I inquired about it Carl told me to send the supercharger into him and he will look at it. I am not willing to do that. I'm not spending money to have him look at it when I can do it myself. I told him I could take pictures and send in the failed part. I asked about the parts warranty and Carl said they do not warrant parts that are shipped out and installed by someone else. The warranty info on his site doesn't say that. Warranty only covers what he installs. BUYER BEWARE if you buy a part from 928 Motorsports and install it yourself there appears to be NO WARRANTY.