it costs about 100,000 to make an R34 skyline legal in the states, on top of the intitial purchase and shipping. there are two ways to do it, by state (usually cheaper) or federally (lot longer process, usually more expensive). in the end they are still right hand drive beasts but they do a buch of bullshit conversions.
adding to the problem, im pretty sure the main company that converst them just went out of business (they were in cali i believe). so the only ones available right now are used ones that are already in the states, unless you are just going to use it as a track car and not make it street legal