TITLEIST TSI4 DRIVER    For the past few seasons Titleist have released a smaller headed, lower spinning version of their driver range a few months after the initial release and this season is no exception as Titleist have now unveiled the TSi4. With a head size of just 425cc it has a much smaller footprint than most other drivers on the market, something that many players may actually prefer.    For better players, one of the biggest killers of distance is generating too much backspin on drives. Once the spin rate starts to climb over 2500rpm drives will then lose optimal trajectory and start to balloon upwards, especially into the wind.  For many golfers, the quest to find a club that can keep their spin rate in the optimal range...