Well at first i thought it was so i was really keen!
I couldnt hear a supercharger and if you remember the top gear episode of the Walkinshaw you will remember how loud the supercharger whine was.

I have no idea what people do to their V8s here for mods but im pretty sure it wasnt Supercharged..

If you go to their website you will see the supercharger pulley. Its tittled as 'Performance Supercharger Pulley'

Intake gains was good. I was lucky enough to have a mate with a 135i and we are very close in stock form so i got to really see how many gains i got.
With the SL55 Intake i noticed atleast 2 car lengths improvement to 100ks.
My gains seemed to come down low, on a roll against the 135i i didnt notice any difference from when i was stock.

Pulley has given me up to two cars as well but the difference is im pulling from a roll as well. I have belt slipping issues sometimes primarily when im on and off the throttle to quickly, other than that its been great. Also note the gains to the pulley would have been enhanced by having a intake

From being two cars behind in stock form from a dig to a 135i i am now two cars ahead to 100.