Glad to be of service! I'm a former '99 M Roadster owner, and I made the first seat bushings as a favor to a fellow member of the Roadfly Z3 forum. Little did I know then that nearly every Z3, M Roadster and M Coupe suffers from that condition at some point; I've shipped thousands of them, all around the world.
I used to have one of your knobs for my old '02 MCS, sold the MINI and then sold the knob to a NAM'r. Great great knob. Was MINIless for a year or so and just couldn't stand it any longer and bought a low mileage '06 MCS back in June. Anyways, when my son was researching the Z3 Rocking Chair issue he says "Hey, all these guys are talking about Whalen bushings". Well I know of only one Whalen. Told him if it's Whalen Shift Machines product to just go ahead and buy'em. He did, we put them in and you sir are a Genius!
I'm with ya steve, don't see many of them but they look sweet. My wife curls her lip everytime I point it out which is everytime I see one!