has to be said that the FAA do not allow foreign reg aircraft to operate in the US unless on a temporary basis.
Do you have a reference for the rules on this?
I personally know a Brit who flew a G-reg there for a few years.
My vague recollection is there are no movement / parking restrictions but some flights need to be notified.
In practice the issue is totally moot because nobody in their right mind would want to do that. You would not want to maintain a G-reg out there, for starters.
The FAA hands out a free (US taxpayer subsidised) set of papers to anybody who arrives in the USA, for flying an N-reg plane.
The whole reason we are having this EASA bollox is because EASA pretends that the FAA doesn't do license validation. The only acceptable method to the morally and intellectually superior Europeans is a bilateral treaty, and it looks like the FAA has refused to sign one (unsuprisingly since they have nothing to gain). If EASA did license validation, like just about every other country in the world does, this whole issue would go away and the N-reg scene would (for the most part) not have come about over here in the first place.