I have a 1997 Nissan Skyline GTS-25; how much is it worth in the states?

i have seen advertisements in magazines and such for skylines starting at 28k. i dont know how much mods have been done to make them leagal here or even how old they are. im guessing they are for the 2dr models though. ive heard that to make german cars leagal here, it costs about $2k. im guessing that its emmition type modifications but im not sure, maybe also safety standards.