Stuff like Chris King and Cane Creek parts are better value in the USA, and easy to bring back. Keep your purchases under £390 and you don’t have to pay import duty / VAT on return.
Intense cycleworks carbine 275 would be on my wish list if I were over there
Frame USA $2249.99
Frame UK £1,999.00
$2249.99 in £ = £1412.76
Plus 20% vat = £1694.40
Plus import duty 6.5% = £1804.536
Plus flight in aircraft and insurance?
So you have saved less than £200, and got a grey import frame that, if anything goes wrong, has to be warranted in the USA. That is if it costs nothing to fly over and isn’t damaged on the way.
To me, personally, that is not worth it.