its all about how much money you have and what you want. i have owned 5 crxs.

i have had a DOHC ZC with a SI tranny
i have had a DOHC B16
i have had a DOHC built B18C
i currently have a 2.0L lsvtec

If your starting out , go with the B16. Its got VTEC, its WAY FASTER than the ZC i ont care what anyone says. the b16s usually have MUCH lower mileage than any B18A engine you can find. The b16 Trannys are way shorter geard than LS trannys. Its a simple swap to do and costs are reasonable.

I would not do an H22, too much money, and no fucking room