Can you tell me if this is a TPMS sensor? This photo is from a set of R85 S-Lite wheels I just bought. I own a R56 Mini and the stock TPMS sensors don't look like the photo. I was wondering if perhaps the R53 has different looking TPMS sensors. I did a search but couldn't find a photo to compare with. Thanks.

 

Your photo looks like a TPMS setup to me.
My recollection is that the R53 didn't have a sensor in the wheel/tire itself. The system worked off the anti-lock brake system. The R56 sometime in '07 switched to the system that used the sensor inside the wheel. Also there may be a bolt hole issue with some R53 to R56 wheel swaps. I know my '09 has larger lugs/holes than R53's.
There may be some info on BERU's site or TireRack that will help you decode what's what on the TPMS sensors. Seems like there was a change in the frequency the system used, as I recall that was sometime in '10 - don't hold me to that but it is my recollection.

 

Looks like a mechanic didn't know what the heck he was doing. That does look like it may be a TPMS, but as pointed out, the R53 does not have TPMS sensors but rather uses the wheel sensors to determine wheel speed.