importing
I brought 2 ferrari's in from europe some time ago - one from Milano and the other from Switzerland. It was not hard to arrange the different activities myself (shipping, insurance, etc).
Shipping is cheap - $700 to $1000 for delivery to NY / NJ. Both my cars went thru Hamburg (I think), though ports in Belgium are also popular. You should take out trans insur also (not $$).
Customs charges a duty, of course - don't remember exactly, but as I recall it was approx $1k per car.
Conversion is the major expense. I had both cars done by Amerispec (they are expensive, though) - but at greatly different prices - see below.
Your cars must conform to 2 different gov't standards: DOT and EPA. The DOT spec requires that bumpers be stiffened, doors have a brace added, side markers be added, etc. This part of the conversion is not expensive - $1K to $2K. Thje EPA conversion is the more expenbsive of the 2, and requires that the car be dyno tested to EPA standards - sort of like what must be done during homulgation by the manufacturers. This is mostly a labor charge, but is more like $10K or more.
The first car I brought in went through all of this; became a normal car. I no longer have this car.
The second car I brought in (Milano) only went thru the inexpensive DOT conversion. Why? There is, or at least was, a little known exemption to the EPA requirements that said "if you are imp[orting a car at least 5 years old for your personal use, and do not intend to resell the car, you need not have the EPA conversion done". The operative phrases are "5 years old" and "intend to resell". I specifically looked for cars 5 years old, and actually waited a few months before importing the car from milano so that it fit this requirement. The other part " intend to resell" - the key word is "intend". The rule does not prohibit reselling; it only goes to INTENT. I still have this car, though there are no restriction on reselling it.
This 5 year exemption is a "once in a l;ifetime" deal - you can only use the examption once, so pick your car carefully. My car remains full european spec (no EPA mods whatsoever), which I of course like.
Please keep in mind that these are the federal regulations; states have their own gestapo. I live in CA, and though my car is legal in CA as is (i.e., is exactly as it came from the factory - it has no cats, but that's OK) - it STILL must meet calif. smog regs for that model car every time it gets smogged. This of course requires a bit of creativity when going to a smog check.
If you go ahead with the full EPA conversion, cats and whatever else is needed will be added and you should not need to be creative.
About resale:
Years ago, when the exchange rates made european ferraris about 1/2 the price of a US car, and the US dealer organization was losing a huge percent of their business, there were a lot of scare tactice usee by Ferrari US to discourage grey market cars. Rumpurs spread that US cars were built better, that dealers would not service non-US cars (be informed that you will NOT have a warranty with an impoirted car), that you could not resell such cars, that you could not get parts, etc. Of course, this was pretty much all bunk - though for a while it did serve to depress resale values since people were nervous. I do not think of this remains - probably since exchange rates have become more equal, and the cost of european cars is no longe so attractive (and thus there are not sop many people importing cars). The full-European car I have seems to be pretty desireable; when people learn is legal without any of the US-EPA crap, they invcariably are interested in acquiring it. So, if anything i think there is no disadvantage to imported cars.
Hope this helps