non si models will be extremely difficult, time consuming, and completely not worth it, upgrade your car, you can find newer civics with popped motors or trans for under 500 bucks...
for the true hardcore first gen crx lovers, and only god knows why someone would be so devoted, i would advise you look into our refrence section on this site
under swap articles...
First Gen CRX FAQ
they have information on what you can salvage from scrap yards for increasing performance on a budget, covers everything from swaps to suspension to brake upgrades...
look into swapping an 86-87 integra motor or for an extra 5 horse, 88-89 integra motor with 86-87 integra ecu and the vacuum advanced distributor from that same integra...
the first gen integra motor will give you a net increase of approx 25 horses, which is quite nice to have, and fairly easy on the budget, as well as a pretty easy swap to accomplish...
if you go this route look for a complete integra as you will need EVERYTHING from SOME mounts, to the spindles, axles , ecu, etc etc, but along with this swap comes a cheap brake upgrade with the teg spindles... may require larger rims to fit the bigger rotors and calipers...
or you can go custom turbo