Ok my 02 has 73k on it and I've been driving it pretty hard the last couple of days (I just got a ddmorks cai so I like the sound haha) but I noticed today while its warm its squeaking pretty loud when I press the gas pedal and while I'm driving. At idle it goes away. Pulley issue?

 

I don't think so. It sounds more like the BPV. Both my 05 MCS the BPV is really loud. I honestly don't know if that is good or bad. It sounds bad but I don' t notice any difference in performance...at least not that I can tell anyway.

 

My serpentine belt is on its last legs as I head to the dealership tomorrow. I hope it has another 250 miles in it! You can see how shredded it is with a bending look with a flashlight.
I've heard that Mini serpentine belts are ready to retire at 50k and mine has 73k. If it breaks it's bad.

I'm also replacing my timing chain and two leaking gaskets for a mid-life rejuvenation of my
straight (Justa) Cooper. My chain is beyond max allowed slack.
On the fun side, I'm re-installing racing stripes of bright copper color over my Hot Chocolate paint :-)