I own a supercharged 54 Manhattan and the blower does make a difference. It's not a neck snapping performer by any means but the five pounds of boost it delivers when fully engaged does provide more than ample acceleration. The McCulloch VS57 supercharger is a pretty robust unit that only needs the Type A transmission fluid it uses as a lubricant to be maintained at the proper level to deliver a long life. There are parts available for them as well as rebuilding services. Having one on a 54 does add to the car's value, as does the stick O/D transmission versus the heavy Hydramatic. The only hard to find component is the fuel pump, which is unique to the 54-55 Kaiser.
This particular example has had the seats and door panels redone in non-original vinyl - but in the correct pattern - and the carpet throughout isn't correct either, but who cares. The matte finish on the paint reminds me of the same treatment I gave my 1950 Kaiser Traveler.
If the car is as solid as it looks and runs well, I'd say the asking price is not unreasonable.