Depends on whether you're talking e90 or e92. If you like the facelift coming out for the e90 then wait a lil bit. If not, then you better hurry up and place an order soon. You don't have to worry about the e92 refresh for a good while. No reason to wait.
Past:'08 E92 335i|ZPP|ZSP|6AT|four (4) HPFPs
Present:'15 Mustang GT|401A|PP|6MT|Recaros
Sig pic unrelated. I like to go sideways and stuff.