The Sr20 swap is good swap and the best one to ask about doing that would be TurboDave. He can get you all the specific on what it would cost to do one into a 240 and a price for specific years. He probably has one or two at the shop.

The B-Series swaps, depending on which you get are really common and parts are readily available. PM VtecKidd and ask him about it, I am sure he could rattle off a quote of the top of his head for any early 90's honda you could ask for. I know he can get you everything you would need if he doesn't have it at the shop already.