finn, you may not have to import them. go to a parts shop and have a look through a piston catalog for similar spec pistons. The easiest ones to fit will be ones with the same gudgeon pin diameter, then check compression height (height from gudgeon pin to top of piston), and check the diameter of the piston. Last thing to check is the design of the piston crown - eg dome, flat top, dished...

I have used Mitsubishi 4G32 pistons in an A14 before with .020 or .030" (.5-.75mm) milled off the crown. I think standard size 4G32 piston is +.040" (1mm) for the A14. but these may not be available in Finland??