I have an 07 Audi A8 4.2L, the coolant in there now is orangish/pinkish color. It needs to be topped off and I am confused as to which Pentofrost to use. Some say the SF and some say ++. I know you have to dilute it 50/50 with distilled water. Does it matter if I use the SF or ++? The car is has about 78K, I bought it used, and I'm assuming it's the original coolant (G12). Let me know. Thanks