my 2011 GS no mods 32K, has been rattling and bouncing over the slightest of bumps, potholes for the last couple of months, changed over the 16" alloys to winters on steelies to see if any difference, but it continues to be the same. The rattle is thru the cabin like running on over inflated the tires. But have checked PSI several times over anywhere from 32-25psi makes no difference to the bounce. Terrible discomfort when driving on downtown roads but car drives fine on highway speeds no vibration , but will stilll make a thunk sound and bounce when going over potholes on the 401/404.