I'm C7 and I think Nars Scarlet Empress is too dark/cool on me. I want to try Fire Down below or Shanghai Express next.
For MAC, I have MAC Red and So Scarlet (same opinion as Scarlet Empress), but I think perhaps I'll try Ruby Woo or Russian Red next and see if one of those does it for me.
Needless to say, I've yet to find the perfect red on me. Y'know, the one you can wear without any other makeup on and it's perfect. *sigh*