Also, I truly believe that racket "stiffness" is extremely difficult to accurately measure. I am personally a bad judge of racket stiffness. When I played with the NS9900 (an apparently extra stiff racket), I thought it was less stiff than my apacs Lethal 60. However, my friend was adamant that the NS9900 was significantly stiffer than the Lethal. One of the advanced level girls I know uses Wilson rackets, and I thought one of her rackets was just as stiff as my Lethal 60, but she thought my Lethal was much stiffer. Also keep in mind that the weight distribution of a racket can be different. The Balance Points of two rackets may be exactly the same and yet the weight distribution could be completely different. Perhaps that's the case with the 8DX and MX80?