Do I need to purchase US ellipsoids before I get the 9006 HID kit from phillips, or can I use the non-ellipsoids. BTW I have 91 535iA US spec. Will I get better results with Euro spec ellipsoids w/HID. Both upgrades are expensive so if the light output is similar with HID for both versions of ellipsoid then I'll just get the US ellipsoids despite what people say.