I chose the M3 because the R4s are made to order. I ride on the hope that M3 asks for better quality control, being customers themselves. I also thought in the beginning that if R4 disappeared for some reason, M3 would still be here to support their product. Well, that was all when the product was just "launched". Now I feel that the R4 and M3 are pretty much the same in quality, although I'm still baffled on how somebody is able to break the spring on any of these. Never had an issue.
Similar threads
