My SL600 is my daily driver and the R4-S pads are pretty great. I've be using the same set for the past 3 years where I would only get about a year and a half usage. They are also pretty easy on the rotors as I would also have to change rotors when I changed brakes. No squeal when backing up and very low dusting. Concerning the sensors and shims: I actually upgraded to the larger '99+ SA style rotors and calipers in front, so I can only say that the rears fit as OEM. Porterfield is a pretty good company and judging by the quality of the front pads I don't see any reason they would make worse pads for the '97 (born with) calipers. As far as the sensor holes, if ANY set of pads doesn't come with the holes (the Porterfields do), just drill them yourself. The pads I have are not shimmed whatsoever.