Hunting for couplers

What do you mean by "the coupler conversion kits?" Bachmann doesn't make any. The Spectrum line uses knuckle couplers compatible with Kadees and all similar couplers. Do you want to replace these? What with?

As for minimum shipping and handling on international shipments: there's additional paperwork involved, which means there's additional time involved. (Even a private mailing costs extra time: you have to fill out a form when sending a package overseas, no matter how small.) There's also (usually) additional packing materials required. If they ship by courier, the courier charges a fee for handling whatever customs paperwork must be done. Either the supplier eats that, or you do. Fact is, the minimum S&H charge just barely covers their costs.

N scale micro-trains coupler conversion kits. The Bachmann Spectrum F7 A-B sets in N scale still come with rapido-style couplers. Which I frankly think is quite stupid.

Best is to get your local hobby shop to stock, or at least. special order the desired parts from wherever they get their stuff from.

-- Why do penguins walk so far to get to their nesting grounds?