Some thoughts.
Tractors are generally designed to meet the EU safety standards. Emissions label is important. Examination at POE to determine whether the engine meets the applicable emissions standards for the year of manufacture.
I've purchased 2 cars that have been delivered to me in Europe. I needed to drive for a certain period of time (not very long) so they could be brought into the USA without import duty saving me 7% (yes, I know they say there is no duty on European cars coming into America but that is fake news). Was in Europe on business, taking delivery there saved my company rental car cost both times. However the cars were built to USA safety standards and could only be driven in Europe 30 days.
When the Euro was introduced as currency the exchange was 0.85 USD per EUR. Now it is about 1.15 USD per EUR. In the 1990s a large number of international companies purchased machinery in Europe and shipped it to the USA pocketing the savings.
Many John Deere, AGCO (Massey-Ferguson), CNH, and Kubota M7 tractors are built in Europe and exported to North America. Those manufacturers would not be doing that if they could build for less in North America.
Until the new European emissions standards come into effect there should be no problem. Probably wouldn't hurt to use the tractor before transit. Shipping in a container is much less expensive than roll on roll off. Make sure it meets all European standards including spectator noise (we always had European sound kits because it costs money to meet the level).
We could never understand why items like cars cost more from Europe while in my industry (construction equipment) we could build the exact same machine for significantly less in Europe than we could in North America. We're not talking small numbers either. 20 years ago the differential was 30%. For one thing US labor was much more expensive than European labor. The cost of medical benefits in the USA added to higher pay drove up labor cost. Yes, that government medical coverage in Europe comes at a cost but that cost is significantly lower than the medical benefits paid by top tier US companies.