Then there's the stage 5. The torque that these produce will require attention to the crank assembly because the torque goes well over the engines intended use.
Back to the original question about stage 2, always use parts that compliment each other. When talking stage 2 here we usually assume that the stage 1 (a/c and pipes) have already been purchased. We suppy a top end combination including cams, pistons, adjustable pushrods, ported heads, and tuning tool. We match the cam and compression to the model of bike, region where you live, and desired power.