I think the average markup paid was around 7k on that forum, but your point still stands. Some people really bought into the fear mongering about scarcity and some people also were just really impatient and couldn’t wait for the market to cool.
I agree that Acura dealer is probably lying, but Honda dealers have not gotten that many FL5s. There's 1072 Honda dealers in the US, and according to that dealership scraping tool the guy on CivicXI built, there's only been about 1200 FL5s brought here so far.
It's because the FL5 is a global car that has to meet Euro noise regs, which are stricter than US noise regs. The Integra is a North American car so they can get away with a louder setup.
If you look at the canadian slides that showed the differences between the base and the type s, it showed that the rear part of the chassis has been swapped (probably reinforced), so that's probably why there's a different trunk floor.
I’m betting it won’t come to the type r just because the FL5 is a global car. The US is a lot more lax about exhaust volume than Europe is, so the Integra can pull it off as a North America exclusive.