Besides the already mentioned exchange rate and your capital base factor I think you should first of all decide on which model of a cat you want.
If it is a production boat your choices are basically limited to dealing directly with the yard or through their foreign agent.
If it is not a production boat but a one-design / one-off build then you can look into various countries and their boatyards
. Check on the yard's reputation and that country's legal
system as to buyer protection. Employ an independent surveyor
reporting directly to you. Check out all tax issues and possible refund issues / refund timings thereof - I have heard of VAT refunds of VAT taking more than 12 months after physical exportation here in South Africa
. Also important are that country's temporary importation laws and handling of shipments for all the equipment
you might be bringing in - large handling fees
/ bribes to clear a shipment can play havoc with your budget
in third-world countries. Make a "professional" cash-flow analysis!
It will of course always be good to know the intricacies and workings of your boat as best as you can, provided you have that technical knowledge / understanding (which I don't have!) and the installation
"finesse" to do a proper job yourself.