My apologies, I thought the E92 had two tiers of sport packages not just M-Sport.
OP, yes, get it.
If you are worried about ride quality, stick to the 18" wheels which m-sport comes with, dont upgrade further. Around 2010/2011, BMW changed the sport shocks to be more smoother riding so if you are reading reviews, keep that in mind.
2009 335i 6MT M-Sport AW/CR Convertible & Border Collie