claudia:
To clarify. I took Cyclic comment to say that there has to be an equivalent EASA STC in order for the modification to be accepted by the FAA. Not all major alterations and repairs will cross the pond. Especially major repairs.
Per the EASA/FAA agreement they accept each others Type Certificates, STCs, Repair Station Certifications (provided they register and meet requirements), and a few other smaller items. But not every EASA country has the same acceptance standards.
Newer EASA aircraft imported since the latest agreement was signed in 2011 have no where near the problems of older aircraft especially aircraft built prior to 2008.
I would be careful to assume that all EASA alterations/repairs regardless of the date complied or aircraft date of mfg fall under a blanket approval with the 2011 agreement.
An imported used aircraft today must still meet its FAA Type Design (which is confirmed with the EASA/CAA conformity statement) with any items outside the type design dealt with separately. And yes I have been involved with a recent EASA import.
W1