Hi guys, so I own an a4 cabriolet 2006 s line... I changed the standard 18inch alloys to 19inch s5 style alloys.... Looks amazing but at speeds above 80mph the car shakes had it balanced twice still the same the guy at the alloy shop says it might be my bushes... He says the change in alloy size could be highlighting it... Could this be true... I don't get the shakes with the other alloys...