If you want to stay naturally aspirated, I think a cam and tune would be a better use of your money. VTEC is overrated. Nitrous is also a much better power/money option. I know you said you don't want to go turbo, but that's more or less the only way you're going to get a "powerful" engine without too much work.Well the mini me is the best power to money upgrade you can do for your car.
oh yeah?With a good tune you can expect between 160 and 180 or horsepower pretty easily.