Are Nissan Skylines allowed to be driven and brought in america?

Sort of, you can import one and register it as a "kit car" and you do not have to convert it to left hand drive to drive it. It will be easier to get an OBD1 skyline, (1995 and older) as newer (r34) skylines will probably not p US emission standards. Older ones don't either, but they won't be inspected for emissions if they are older than 1995. I believe The R33 skyline meets crash standards in the US, so your safest bet is a 1993, 1994, 1995 Nissan Skyline. There are a few websites that officially import cars such as this from japan as well.