I have an opportunity to pick up an extra Supercharger from an '05 R53.
(Sorry no pics)...
Overall the SC appears to be in very good condition except for some of the rotors showing some flaking of the Teflon coating.

In your opinion: Does the Teflon coating really make that much of a difference to you guys?

Upon further evaluation (if the end play is within specs), I am thinking about removing the remaining Teflon from the rotors as I (personally) would want to avoid having chunks of Teflon making its way into the/an intake/engine.

Side notes:
The oil from the snout was full and a slightly amber/red in color.
The PTO/water pump end (gears) look to be in excellent condition and the fluid amount was marginal but light in color.
I didn't have a dial indicator or feeler blades with me at the time; but has little/very little end play and no scoring.

Thanks.

 

If I was in the market I wouldn't have a preference on teflon coated or not. Mileage and condition would be my first priority.

I would definitely remove the teflon, having flakes around in your intake can never be a good thing. I do wonder why it is coming off, I personally have never seen it before.

 

It's not uncommon for that teflon to separate from the rotors. Personally, I would not buy an S/C with partially separated teflon -- makes it easier for the balance to loosen.