Car appreciation... the aesthetics, the engineering, etc

They're good for off-the-line grunt, but as you say its a parasitic system running off the crank.

The Jag XJ supercharger was said to take 100 horsepower to make 400.

A turbo charger has to spool- a boost threshold below which the car is sluggish, but above that the turbine will keep adding power as the revs rise, running on the exhaust gasses to make that power.

Supercharger for drag racing where you need boost off the line, turbo charger for circuit- where you can keep within the rev range that is supported by the turbine.

I've always wanted to try a Twin Charged engine. Have you any experience?