Ok, so I bought a modified 02 MCS. It has the following mods:
Eibach coilovers, Brembo blank rotors with Hawk HPS pads, Alta 15% Pulley, Alta CAI, GTT Top Mount Intercooler, Magnacor Wires, NGK Plugs, Megan Racing header, Magnaflow exhaust, MTH Tuned ECU.

It has 93K on it. Yeah, I know, miles and mods, but I live on the edge.

Issues with the car:

1. Ringing noise from under the hood on acceleration. Sounds like an old-style phone ringing while on boost. I searched and believe this is probably the SC, although the car runs like a champ and the Autometer boost gauge is registering 12psi.
   
2. A dull, knocking vibration during acceleration in 1st and 2nd from 20-30mph. Then this disappears. The vibration disappears when in Neutral or when the clutch is depressed, but also disappears when the transmission is engaged and the car is not accelerating. (vibrates while accelerating, gone when coasting, starts vibrating again on the gas) Not RPM dependent, does not occur above this speed or at the same RPM in other gears. I've driven cars with out of balance crank pulleys/ dampers, and it feels similar to this except it does not happen in all gears. I've also felt cars with a chattering clutch or out of balance flywheel behave similarly. Ideas?
   
3. Lastly for now, the driver's side door brake no longer works. Does the door panel need to be removed in order to replace this part? Do any dealers (Classic Mini I've perhaps read) offer discounts on these parts?

Thanks for listening and thanks in advance for any thoughts.

 

Found this link on our site that may answer question #3.

 

Bingo! Well-done. That is EXACTLY the info that I am looking for. Now I just need to order the part.

Thank you for the answer.

Just an update to the other question, I am not convinced that the ringing is the SC. It was happening under vacuum, although the supercharger is still spinning...