I need some help. I currently play with both a Head Liquidmetal 4 & a Liquidmetal 8. I feel that I need more power than the 4 can provide. But I have been playing the game of tennis on and off, for the past 20 years. My question is, should I move up to more of a tweener racket or should I stick with the Liquidmetal 8? (Game Improvement Racquet) I'm a 3.5 ranked player.