Alright, my dad has a 1995 Integra RS non-vtec with 140,000 miles. The timing belt (?, I know nothing, please bare with me) is broken and possibly there is more damage but they can't be sure until they fix the timing belt ($700). The car still looks great, should we try and swap the engine with something better?

Whats the difference between JDM and USDM?

How would I know if I was getting a piece of garbage or a good engine?

Its really hard to find good information on the net about this stuff, everyone is just trying sell something, please tell me what to do.