I have a 1992 300zx turbo and need to swap the old engine to a rebuild japanese engine. I'd like to know how much it will cost to remove and replace the engine?

I don't think many would be able to help, but welcome to the forums anyway. A great place for help would probably be twinturbo.net as their forums are for z32 owners whereas this is more of an s30 forum. I'm not sure as to what you're referring to by "japanese engine" because I'm pretty sure the american z32 and japanese fairlady z32 shared the same VG or VQ engine. I forget which but I'm pretty sure it was a VG since it's from the 90's.