The Boss 302 oil cooler will put a biger cooling load on the radiator . When i did the change over on my car i did oil cooler & Boss 302 Radiator. The new Track Pack that come on the 2013 mustang the oil cooler also comes match up with the Boss 302 radiator .The stock grilles on the 2011 & 2012 GT block a lot air for getting into the radiator so I also change over to the Roush upper grille to help with cooling. For people that are thinking about doing this change i think you should do Radiator and oil cooler at same time but that just me .