The CTS has a 70.5mm center bore and 5 on 115mm lug pattern. If the wheel has both, it doesn't need hubcenteric rings. Many wheel manufacturers use larger center holes and replaceable rings so they can fit a multitude of cars. My Mille Miglias have the 5 on 115mm, but have a 74mm center bore, requiring 70.5 rings. Mine are aluminum rings.