I don't know the ideal offset for 240z's or 300z's. I don't own one. I drive an AE86, and my buddy picked these up in japan, we test fitted, and they were a little tight (offset was a bit higher then the ideal offset of the 86). But these would fit perfectly for a 240sx. I don't know if 240z's are the same or not, all I know is that they share the same bolt pattern. True and round? Like I said, I just test fitted them, never mounted tires on them or nothing. Judging by the condition, I'd say that they're straight. There's no dents or anything of the sort. I'll go to the post office and ask about shipping when I get the chance. Shoot me an email so we can talk about this in private.