I believe your best options are the JDM brown top ZC... ~130hp, then the teg engines from the same year... ~112hp. A B16 can also be dropped in, but that requires a mount kit... not sure how close to "fabbing" this comes.
Not to steer you away from our site, but this site, just by chance has become a haven for the 88-91 CRX. a great place for you to learn much much more about the first generation CRX/third generation Civic is www.redpepperracing.com
A forum community dedicated to Honda CRX owners and enthusiasts. Come join the discussion about performance, modifications, classifieds, troubleshooting, maintenance, and more!