I had these installed the other day along with the AFE filter. There is a difference, but it isn't huge. The difference was enough for me to pull from a white CLS55 today from 60 mph (slighly, but enough of a difference to warrant, at that momet it was priceless).
I definitely hear more intake noise around the 2.5-4k rpm mark. I did not notice any difference when I first tried them in 93 degree weather. When I really started to feel something slightly extra was there was at night. The reponse with the filter is slightly improved as well.
For what its worth, RPI says that since the M3 has a cone style filter the ram air effect is not as pronounced as the flat filters in the 335 and M5/M6. Don't expect as large of a gain, but it is a worthwhile one for the price.
Considering ASR couldn't deliver, RPI is the way to go and they will include install for the price.