I think that Eaton (roots) type of chargers are meant for different type of engines, big massive and with lots of torque - American muscle cars for example...our little D engines struggle when we engage the AC on, so u imagine how it would turn that big boy...in fact it can consume above 100bhp when at full load.
http://www.eaton.com/Eaton/ProductsServ ... PCT_221789
http://www.autozine.org/technical_schoo ... 1.html#TVS
However there are very few centrifugal superchargers that can be mated with our engines. 
I think, and correct me if i am wrong, only Rotrex and Jackson produce such, but at a price of 2 cars in good condition.
The centrifugal type of a supercharger is the most efficient one because of its lower working temp and low friction, but it has its flaws. It uses a very complex gearbox that multiplies RPM from the engine to 60-80 k but it does that following the power band of the engine and should be tuned to match it..
To keep it working under such conditions they use very expensive bearings and oils. 
The maintenance of the components is a problem in my opinion. Maybe someone who uses it can bring some more light on the matter.
I think someone mentioned here about G60 SC from VW Corrado, but would not advice putting it on any setup as it proved to be very unreliable.
Personally i wish to go the centrifugal sc way soon, but instead of buying the above brands i want to couple the compressor side of a gt15 or bigger turbocharger to an Switched Reluctant electric motor capable of high speeds..not exactly sure if i could find one though ...if anybody here can help with that it would be great:)