If you want to do it safely, a complete fuel system and a standalone or otherwise engine management system (such as Hondata).

Drag Kit, Hondata, RC Engineering Injectors, New Clutch, New Flywheel, New Fuel Pump, New Oil Pan, All the lines and crap.

You're spending ~$5500 for a good setup, to be as reliable as you can without doing engine work and you could run 7-9psi on it.

Im not sure of the gains on a Civic though, Id imagine ~100hp.