The other posts have summed it up nicely, the differences between the locality names (say Columbian vs. Nicaraguan) is generally just the locality, but you'll also get little differences in the phenotypes (the "look") that can help you identify, and in the example I used, size sometimes (Nicaraguans tend to stay smaller than Columbians). They are still the same species (BCI - boa constructor imperator).

When you start to look at boas you need to know that they tend to be a lot more active than balls and that can be taken as them being more bitey, which is hardly ever true. People say that Nicaraguan boas are pretty snappy boas, but I have a baby Nicaraguan and she has never so much as hissed at me. I've even handled other nics that were puppy tame.

Okay, I'm starting to rant lol. Just don't be deterred by the activity level, boas are great and they have so many different localities that you can choose from for their little quirks that you're bound to find a snake you'll love.