I'm actually not a fan of the M3 shifters, I think they're a bit of an eye sore and too plastic fantastic. I was thinking of switching an M3 to have those, but then saw them in person and they weren't any better.
Personally I like these, cnc milled and anodized, and illuminated M3 paddles:
http://www.m3post.com/forums/showthread.php?t=431374