R53 Supercharger pully

[siwil1]

Ive just inherited (long story) my sons 54plate cooper S. It feels incredibly quick, definitely has a sports exhaust and I'm wondering if its had some form of modification via the pully.

Is there an easy way to tell if anything has been done?

[CO2000]

Is the pulley different from stock? Shorter belt fitted could be a clue?

[CarsOrBikes]

The end of a standard pulley is very plain, most aftermarket jobs have a ring of bolts which is the eco mod style.