That's a good question. I know I have my nitrous and I haven't even used it yet, but when I want to it's there. I don't see any reason why I would get rid of it it doesn't do anyting when I'm not using it...
Superchargers of any kind......turbos are also superchargers...make an engine very efficient. More power and as long as they're driven with respect to the go pedal, more average mileage than a naturally aspirated engine......so that's why I asked. It seems if they are so great people would hold on to them. I just scratch my head.