I need to buy a b16a for crx NEW/USED

3 people could most defintely install the engine. One person could. Just as long as you have the knowledge it takes to get it done. Here are some places to get motors that i can think of off of the top of my head:
w w w . i n l i n e f o u r . c o m
w w w. j d m h o n d a p a r t s . c o m

As long as you know how anyone can do it.

I would suggest using www.jdmhondaparts.com , that is where i got my b16 from and they are fast with shipping. The motor they sent me started up perfectly, the transmission has no issues with shifting. They even sent me brand new genuine Honda shift linkage. There are, however, some parts you will need to get regardless of where you get it from. Timing belt, water pump, new NGK Platinum Spark PLugs, oil and oil filter, coolant. Some extra parts I needed to buy were the bushings for the shift linkage and alternator belt. And you can definately install the motor with 3 people if you have a good area, the know how, a Honda service manual for you car (and maybe the car with the donor motor). I did my swap with a couple friends in my garage/driveway. But like I said, make sure you know what you are doing and that you have the space to do it and you should be more than fine. Hope my information helped you out...