I installed a supercharger on my 4.3L earlier this year. Because I'm running a 5 speed manual trans, the S/C was not compatible with my set up. When I would disengage the clutch the engine would surge 500-700 rpms due to slow idle decay. I tried working with the owner of the company and we were unable to resolve the problem. It got to the point of where he would not answer emails and I always had to call him to get a non answer to fixing the problem. I was strung along to the point that when I wanted to return the unit for a refund less his 25% restocking fee he refused due to being over the time limit. Here's where it gets good! I found an office of the Better Business Bureau in the city where he operates. He is not a BBB memeber but they, the BB, will take the complaint. It was a matter of a very few days of filing my complaint when he called me and wanted to settle the matter. I don't know what they said or did but it worked. I thought I'd share this in case it might help someone with solving a problem.