The polly mounts make alot of vibrations with the big V-8, even more when it goes into 4 cyl mode
hey when you mean viberation, is it when driving and the streering wheel shakes?
2008 Crimson red Grand Prix GXP:
Mods are: K&N Air Charger intake, Power Aid TBS, Hogan 3inch downpipe with magnaflow high-flow cat, Magnaflow cat-back, Smoked LED tail lights and GM pedals (GXP)