[Gonthrax]

Before I say any of this let me say that I am by no means an expert on this, you probably know more then me about the subject, but I will relay to you some info I have found out on this board.
There is a company called G&K Conversions in Costa Mesa CA. They can do the conversin for you, as for how much it will cost, I don't know because I haven't called them yet but I'm sure that will be the second highest cost aside from the car itself. Now the downside of going this way is you have to do all the research and foot work yourself, ie. Finding an acceptible skyline to buy, finding out what it's current emission stats are, telling G&K what they are so they can tell you if they will convert it or not, buying the car overseas, arranging for shipping and all that great stuff. I don't know the little ins and outs to keep from getting your skyline siezed and impounded because you forgot one little bit of paper work so I can't help you out with that but I'm sure some one on this page would know.
Oh, btw, the guy you need to talk to at G&K Conversions is George Sr. at 714-545-9503.

Hope I've been of some help