I have been trying out strings for a little while for my sp tours and just popped in a fresh set of tonic which I was able to hit with today. All I have to say is wow! When I was demoing rackets I had a hard time choosing between the sp tour and the Becker 11 mid. The tour had the incredible groundstrokes but the mid had by far better serving and vollies. Now I'm so glad I went with the sp tours because with tonic I finally have my flat heater back but also the rediculous kick serves that I'd been relying on since switching. Also the string just feels so comfortable and packs great pop so my vollies are going deep and not hanging out at the service line. It really is incredible how the right string can affect your game. I'm not saying it moved me up from a 4.5 to a 5.5 but it did help me dial in the shots I already had in my arsenal and let me swing with confidence. I have also tried champion's choice, bg/titan, silverstring/x-1, sppp/x-1, big hitter blue/x-1 in the past month and my arm really cannot take a poly, even a soft one. The tonic is strung at 53lbs. And what makes me even happier is I strung it myself and it has so far survived 3 hours in the hot Florida sun.