Early in the article you mention the trap not being "porcelinated" which I assume means glazed. Whetther the trap is glazed or not does not impact the performance of the toilet. If the glazing is not done correctly, snags can be created which catch toilet paper and affect the performance of the toilet.You must also look at the size of the trap or passageway through the toilet. Most toilets in the USA are of the siphonic design in which a siphon is created to pull the waste down. In order to create the siphon, their trap must be small and they will glaze it to maximize their performance. But the small trap tends to create clogs.Caroma uses a washdown design in which all the water comes from under the rim and washes down the bowl. Caroma also uses a 3.5 to 4" trap which will not clog, and in some cases can pass a baseball. The trap in a Caroma toilet is usually unglazed.I would suggest you ask for the Sydney 305 from Caroma. It is their new low cost model. It will flush 700 grams of solid waste on the half flush and 1000 grams on the full flush. Note that Caroma is the only toilet manufacturer to test their toilet performance on the half flush.