I have been using the Luxilon M2 pro 16L strung at 54:39 for the last 2 years. I like it....but its kind of all i know. I had my fun with natural gut but got fed up breaking them every week so i did a little research and landed on the M2s...i seemed to like them so i just stuck with them. Now I am switching rackets and curious about maybe mixing the strings up a bit as well. The Spiky Sharks seem interesting...how would they compare to the M2? Would love to hear other suggestions as well!