The Stage 4 Kit, particularly the BBR Tuning Billet Aluminium High Performance Cylinder Head 66/80cc upgrade adds quite a bit more power, and keeps the temp down. It's well machined, came with an upgraded spark plug and has lived up to advertised specs! Customer service, shipping turn times and quality have all been top notch! I'll never order a China clone off competitors site again.
The BBR Tuning Billet Aluminium High-Performance Head will give you performance without sacrificing style. Designed with billet aluminium, this head is made for performance engines as well as any non-performance engines. Built with a rounded and squared shape, this head cools your engine faster than standard heads while giving you 20-30% more power to your engine. This head might look small, but it packs a punch better than those round heads and most "ashtray" cylinder caps. If your engine wants more power, give it the BBR Tuning Billet Aluminium High-Performance Head and you'll feel a big difference when you hit the throttle.