Real world experience: 1998 Land Rover Defender 90, Station Wagon (that part is important). Purchased outside of London (Surrey, if you must know, but no fringe was involved) late December, 2019 for 10,000 pounds sterling. Drove in Germany until I hit the "25 year point" (August 2023). 25 years is based on the manufacture date. Heritage certificate is helpful, but date of first registration is incontrovertible.
Shipped from Southampton to Baltimore for 3000 pounds. I think that converted to around $3600, it wasn't much more than that.
Important point: Because it was listed as a "station wagon", and because it had seats in the back, it was imported as a CAR, with a 2.5% duty (of the purchase price of 10,000 pounds. Missing seats would have caused some consternation, pickup truck version would have absolutely been an issue, and would have bumped the import fees to 25%. Also, emissions is not the critical point in the 25 year piece, "Meets DOT Safety regs" is the critical part. That includes air bags, ABS, back up cameras, whatever was required the year it was built. Nobody cares about what side the steering wheel is on, but I have gotten a lot of looks. The NHSTA has a "good list" of vehicles that are pre-approved. No Land Rovers are on this list. The Porsche list is pretty entertaining though.
So then it was a drive from Baltimore to Idaho with a side trip to Maine (long story). Registration in Idaho included sales tax on the value declared to Customs. Parts readily available, if Rovers North doesn't have it, they will get it from the UK. All in cost was less than $20,000, but they are more expensive now. The really good news is we're up to the 2000 model year, so Td5s are now safe. I actually like my 300 tdi, because the only thing close to digital on that is the EGR system, and that's coming off when I get around to it. It's completely analog, so I'm not too worried about surviving an EMP attack.