I think he added the assumed horsepower gain to the 265HP rating of the engine at the crank. If it was dyno then he would have gained 80-100HP minimum at the crank to pull 292HP at the wheel, assuming a driveline loss of only 20%. Using the 20% driveline loss gives you 212HP at the wheels with the stock 265HP rating.

If you added the K&N and exhaust why did your peak HP go down the rpm range. The X is rated 265@5600rpm and 284@4000rpm.