H22A (US) Vs. B18C (US)
If your plan to go turbo in the near future, I wouldn't pick the H22A. Although, built-in advantages of the H22A, such as a closed deck, bigger bore, and bigger stroke. What the H-series lacks is the way the cylinders are lined; the sleeves in the H-series are much thinner. Because of this, the cylinder walls of the H22A can't take high-boost. Unlike the race-prepped B-series, the cylinder walls are thicker, making it possible to boost 15 psi on stock block.
If you plan to go turbo, the B18C will be the better pick. You can boost 10 psi safely on a stock block. I have a buddy, boosting 10-15 psi, and its a daily driver.
With the H22A, you'll probably invest about $3,xxx to $6,xxx to boost over 15 psi. Example: Bottom-end work, which includes sleeves, pistons, crank, and etc.
I hope the information I have provide will help guide you in the right direction.