Honestly I wouldn't upgrade the board or the bolt. I left mine all stock and it runs fine. If you play tournament you can only shoot 12.5 anyway. If your playing scenario then each one has different rules settings and you already said that your able to shoot 15bps. Keep the money and buy paint, pods, mask, pads, etc.
Never argue with an Idiot. They will drag you down to their level and beat you with Experience!
It's not the WILL to WIN, but rather the WILL to PREPARE to WIN that will make the difference!
In-Hoc Signo Vinces!