of all the stuff that goes into making a quality boat is pretty much the same anywhere in the world, if you use the big name brands, and if the yard you use has some volume to get proper yard discounts.
The biggest variable IMO is what method you choose for the build, and the number of manhours and hourly rate these cost.
The actual labour cost for say a basic 40 ft cat will be between 15 and 30% of the total cost, depending on the required finish of course.
Never underestimate the value of experience in the build method you choose, this is an important quality factor.
An important issue IMO is to choose somewhere that has a good sub supplier infrastructure be it for parts
or specialised skills. This can be lacking in some of the SE Asian markets in the type of build you would want for a lightweight boat.
Hope this helps