You might try Mazda Mini recyclers in Rancho Cordova?
I have bought about 6 over the years from them good condition and low miles. Not sure about the market price with them because a Super Charger shortage scare was started a year or so ago by some uninformed MINI owners that feared theirs would go bad and thought replacements hard to get. MINI and the recyclers will have MCS SC for the easily the next 5-10 years.
Hope this helps?
Mazda-Mini Cooper Recycling
11315 Dismantle Court
Rancho Cordova, CA 95742
877.280.3100