I have been playing with the Flexpoint for the past five years, it has suddenly started pinging, thinking it was cracked I bought a Microgel (both radical MP), I also hear pinging from that racquet which seems to be worse than the flexpoint. I do use a dampener and have the same string and tension I have always used. Do I now try the Youtek, I want a nice thud from the racquet like I used to get from the flexpoint. Also what does L4 and L5 mean on the throat of two different racquets. I know it is swingstyle but what is the difference between the L4 and the L5?