Whats the differance between R4 red and R6 red colors

mrspeeddemon said
check out my car- its R4 if I don't wash it every week and wax it starts to look real orange- but its also the originaloxidized paint.- when I got it the deck lid was so oxidized that I thought it was off of a white car! check my sig! :drinkers:

Thank you for the link to the color. I thinks thats it .Ill have to stop back at your site when i get a few minutes to read about your car.