In 1994, Congress banned the sale of functional, high-capacity toilets. Not coincidentally, that was the same year as the assault weapons ban. From what I can tell the EU and Canada have share the same restrictions. Is there any country that still sells high-capacity toilets? Thailand? Mexico? In the 2000s, I imported a 3.5gpf toilet from Canada -- best decision I ever made.
Not interested in hearing how government-approved low-flows are great now. I'm sure your 130hp Prius is "just as good" as a 500hp Corvette, too. High-capacity in a modern design is what matters. I don't live in California, "saving" water isn't an issue. I want high-capacity toilets solely because the government doesn't want me to have them.
It is not illegal to buy, import or possess a bootleg toilet, incandescent light bulb, or high-flow shower head. It's only illegal to manufacture them in the US.