Well from what I've heard turbos kill gas mileage and aren't as reliable as NA cars. The LS/VTEC would be a monster either NA or turbo, but in a lot of states swapping a head from a completley different engine is illegal so if it was like a race car only or you just never get pulled over you should be ok. On a side note isn't '91 the last year of the CRX? I have a hatch with a b16 and love it. but, if I had the money, I would have gone GSR or K series(just to be different, but that would have been $6500+). I've heard h22s in hatches are amazing but it is one of the heaviest 4 banger engines honda makes(45lbs more than a B series).
In the end it's all about what you want, if you want to be different, go with the H22 hatch or ls/vtec. if you want something that's just better than stock the turbo si might be a good choice. Personally I'd stay away from a ZC engine just due to lack of aftermarket support for it.