You're going to need the tranny, ecu, axles, & different motor mounts to pull it off. Most of the parts you need can be gotten from the car that has the motor. The mounts will have to be either custom made or a pre made kit just for it. They won't be cheap. check out www.hasport.com for more info on swap parts & pre made motor mounts for stuff like this.
if still you so decide to keep your stock motor, get a JRSC. but the amount of money that you're going to spend on swapping in an H23 is nothing compared to the price of the JRSC. especially since you mentioned that you're getting the H23 for free.
Just remember, everytime you gain some horsepower, you will lose something in return. Everything in cars is a tradeoff. For example, one of the things you lose is torque when increasing the size of your intake/exhaust. With a turbo or supercharger, you may lose longetivity on the engine, etc etc.
i hope you aren't too attached to your a/c and power steering cause inorder to put in an H-series motor into a civic, you have to take those things out...i've heard of a couple people custom fitting them by cutting the chassis...but remember people, it's a unibody chassis so don't cut too much...As for the mounts, i'm pretty sure place racing has a set too... good luck
This brings in a good point. Yes you lose torque, but only in the low end and you gain much more in the high end cuz you can push more air. Our small civic engines are designed to rev high to make power. So most of our useable power is in the 4000+ rpm range. That is a great advantage we have because when you shift at redline, you don't go back down to 1000rpm to grab the next gear. You're still in the useable power range. That's why small things like a better breathing intake, throttle body/manifold, cams, headers, exhaust, etc,. make such a difference on our cars. (not to mention how light our cars are). And to expand on the advantages and disadvantages of turbo/supercharging: Turbos can produce massive amounts of power, but they have to spool and build back pressure before they can produce. On the flip side, a supercharger will give you instant power to your engine because it's constantly running, but because it is constantly driven off a drive belt on your engine, it will rob a lot of high end power because of the massive amounts of energy being sucked from the engine at high speeds. So all this being said, modify the car based on where you're going to use most of the power. You're h23 pushes quite good power, but your car will handle like a pig because of the weight upset. Then again it's free. :