These all weren't new enough to be dialed down. They were all fixed belt driven blowers where the pulley size dictated the boost level. They weren't crazy high boost but they were sure noticeable and whined like crazy. If they are adjustable then yes you will want to dial down when you don't need the boost. It'll decrease cylinder pressure and make the engine last longer and it'll help you keep your foot out of the gas too. A blower basically just increases the compression in the cylinder. That's it's sole job. With more air going in so does more fuel. It's belt driven off the serpentine belt or has its own and if the engine is spinning so is the blower so it's compressing regardless. The new setups may be a little different but in a nutshell that's the way they work. Also with a blower, at least in theory, you can get an increase in MPG. We found that wasn't the case because of the temptation to mash the gas.