Great car btw, lol.
Well considering I also own an HF, I would say that you are out of your mind if you are trying to upgrade the D15B6. Granted you can make good power even with 8 valves, The engine is not at all built for power. The intake is much smaller, the exhaust is tiny. the valves are tiny, the transmission sucks for acceleration. Not to mention the rods are made of toothpicks.
So just enjoy it as the little fuel efficient car that honda designed it to be. Oh, btw, what kind of gas mileage are you getting out of yours. I only get 45ish with mine, but it seems a little low, because I drive it like a grandma and almost never shift past the shift light.
Oh, and mine has a Megan Racing header on it, and a aluminum flywheel, and aluminum underdrive, and AEM cam gear. Cars slow as balls.