This is a funny subject to me. Let's see ... If I take a 2009 Jeep and put a Hemi in it ... does that make it illegal to take across the boarder? Jeep (the company) didn't do the work ... instead ... an aftermarket company did the work (hypothetical ... as I only own rovers!)
Let's say I own a 2009 Full Size Range Rover ... and I make a stretch limo out of it ... 52 feet long and 25 passenger ... is that illegal?
Technically ... yes, but really?
I have a friend that recently did the unthinkable. Bought a "goat" body from Land Rover (a goat is a show truck shell only), Bought a chassis, and a crated 300Tdi. He built the most fantastic 2009 110 I have ever seen. He went down to the DMV, got all the receipts for work performed, and they assigned him a VIN as a custom build. Would he dare cross the border in this? Would they take his truck?
Technically, it is a truck never offered or sold in the States ... but it is a legally built truck.
If he got the wrong guy in the wrong mood at Customs ... technically, they could make him jump through hoops, but in the end, ... I think he would "overcome" the obstacles!
This area gets to grey so fast that I don't think there are any black or whites.
Technically (by the letter of the law) Chip Foose breaks the law with almost every car he builds, but he builds some killer cars and they even make a TV show out of it!
I think this goes back to what other have said regarding the fact that for the most part, the border patrols are looking for illegal contraband or illegal alien. They are not really nit-picking over the legality of a particular car or truck (unless it is stolen!).
Carry on.
Just my worthless two cents.
D