Supercharging help and search

[Greekthang]

Hello guys. My friend recently swap a Euro 3.2 into his 325 with a Euro 6 speed tranny and once again he is looking for more power. Crazy guy. I told him to get on here but hes lazy so I am doing the work for him. Anyways I was wondering is there anything out there that performs better then other superchargers ?? I think he has read up on alot and he is looking for a supercharger that put no additional stress on the motor or the blower at idle. I read somewhere that some of the blowers have clutch releases and disengage at idle. Anyways if anyone on here is selling one used or if you can give me advice and direction to pass on that would be greatly appreciated.