Oh, it's *only* vibration? Then yeah it's possible that something is loose or vibrating against something under your car. Must have misread your OP.
2008 E90 335i // Black Everything // photos
COBB tuned / QTP e-cutouts / Helix FMIC / cp-e DCI / AWE BOVs / Black M6 wheels + Toyo Proxes
(and yes, I am a girl)