Ryan, I hate to break it to you... although your buddy at work was indeed very correct, your car doesn't have a supercharger, it has a turbocharger. All 1st Gen Ses came with superchargers, and all 2nd Gen Ses come with turbochargers.
So the pulley upgrade is only valid with 1st Gen MINIs. That being said, you can still get some nice gains with 2nd Gens by upgrading the intake, the exhaust, and getting a good tune, like from Jan (Revolution Motor Works), as is happening tomorrow and Saturday at Mach V. I believe there are other notable upgrades, but I am not a 2nd Gen guru... so I'll leave that to those that are.