An engine swap into a 240sx will probabaly never be original again, especially the ones you're looking at. Just because everyone and their mother has an SR doesn't make it a bad engine at all. BUT, a CA swap in an S14 is for less common than an SR. Not a flame but how long have you had your 240? I'm just picturing you hopping on the bandwagon within the past year or so, and then bashing the popularity of the SR swap. I'm probabaly just being cynical but I smell hypocrisy.

Want originality? Sell the 240, or swap something you've likely never heard of in there. If you'll settle for cost effective and relatively easy fun while not being the epitome of the bandwagoneer, go with the CA. Again, it won't be original and the SR starts with like 25 more hp stock, so the choice is yours.
Good luck.