which engine?

How much harder/more expensive would it be to do an engine swap with a b16b vtec or b18c vtec engine than just putting in the b16a? The 20-25 extra hp would be nice, although not really necessary, and I'm wondering if it would really be worth the extra time, money, and effort.

Well the swap is almost exactly the same.
Infact I think its exactly the same, unless you do a B18c, inwhich case you have to run one extra wire for the Inlet Manifold solonoid.

All B series engine's are essentialy the same extranely, and doing the swap is pretty much the same.
All you have to do is pay the extra $$ for the better engines.

The b16b would be a little bit harder to put in since it is an obd 2 motor. To do this swap you would have to get an ecu jumper kit which allows you to hook in an obd 2 computer in an 88-91 civic or 90-91 integra. You can get these at jdmhondaparts.com.

The B18C engine I'm looking at has a hydrolic tranny that comes with it. Can I put that in my car, or would hte switch from a cable transmission be too hard?

you cant use the hydro tranny on your car. you would need to get a cable tranny. but i bet you could get alot for that gsr tranny. more than enough to cover the cost of a cable tranny. you cant swap your tranny from cable to hydro. well you could but it would be really hard, you can do anything if you pay the price. your car comes cable so putting in a cable tranny is easy