Replaces OEM with these, mainly for autocross. The embedding process is a little different, but once it was complete, these pillows really came to life. They squeaked a bit for the first few hundred kilometers, but now you can't tell them apart from regular pads. Until you heat them up and they keep working! The only real downside is that they generate a lot of dust, but to be honest I find this to be a last that works just as well on the street as it does on the track.