Welcome! First of all, you are probably the only member in this club that actually drives their 240Z in the snow (at least nowadays ), so I hope you don't plan on driving it in the snow anymore. I don't know much about Omaha as far as Z parts are concerned, but there are some very reputable companies around the country, particularly in Southern California that most of us have had very good experiences with. There's Motorsport Auto in Orange, CA (motorsportauto.com), who will give you a discount if you mention that you are a member of this club. There's Black Dragon Automotive in Lenexa, KS (blackdragonauto.com). An independent guy in Texas who I highly recommend is the-z-connexion who sells a lot of NOS (new old stock) 240Z parts on eBay and has very reasonable shipping charges. He will also work with you on the shipping charges if you purchase multiple items and will combine shipping. Here's a link: http://motors.search.ebay.com/_W0QQsassZtheQ2dzQ2dconnexion
Good luck with your project!