I also have a Pocket Rocket (great first wave board) and as I progressed, I wanted more speed from the standard thruster setup that was supplied with the board, so changed it to a quad (2 x G5 4.5" sets). This loosened the board up nicely, but the speed increase came when I fitted a pair of smaller 3.5" fins at the back. I'm 72kg intermediate paddler. I loved the Pocket Rocket for waves (upto head high) and flatwater paddling with the family, but have just moved to a SMIK Hipster Twin 8' for much improved speed, drive and looseness.