b16a1 comes from crx sir, b16a2 comes from del sol top model, most ppl are stretching when they put a new engine in their car, plus some engines are just easier to swap over, i could spend 2400 for an h22 to put in my rex instead of a 1300 dollar b16 and have 40 more hp, but then again itd be a pita to get it all installed and i dont want to do all the work, so id rather go with a smaller hp engine and have the extra money to do something with suspension, looks, turbo, etc. also uve got to look at compression rates, the b series engines typically come with higher compression so someone looking into a forced induction setup would possibly be better off looking into something with a lower compression, instead of an already great built engine.