A cheaper option that I think will get you more power for a naturally aspirated car is going for am LS/VTEC. This is a B18B (or B18A) bottom end with a VTEC head, for which your cheapest option is probably a JDM B16A from a Civic SiR1. These are all the rage among the hybrids now. If you have more money and want to get crazy, I'd say build the same thing, but use a B20 block from a Honda CR-V with a B17A crankshaft (which was the engine used in the 1992 to 1993 Integra GS-R), and use a B18C1 head (the B16A head can move 267 ft^3 of air per minute, versus 288 ft^3 for the B18C1 head). Again, this option is more expensive. You'd probably pay say about $1,400 just for the block and crank (no rods pistons included!) here, and perhaps another $800 for the head. You can get a B18A/B bottom end much cheaper, say $400 or less.
Consider this: I picked up a B16A "spare" bottom end this weekend for $150, and it's mint. Piston domes have not a scratch on them, and the cylinder bores are also very clean. You may pay more for a B18A/B block these days just because more hybrid builders are looking for them, but a B16A bottom end is actually a better piece of equipment (better oil squirters, better rod/piston materials, superior rod/stroke geometry).