There are cards ending with 00, 01, 02, 03, 04 and 05, etc. It is probably a revision number. If you look on eBay, the cards with the higher ending numbers are selling for more - there is a big difference between the 07's and the 00's.
Well, i choice the final number 0, the number 7 is champion edition.
And if I'm not mistaken the champion offers something more for audiophiles, but does not add much for competitive fps.
Although I wonder performance between 0 and 4 for the sound positional