Modern Prefab or Modern with Stock Plan

My wife and I are looking to build our first home.  Are hopes are somewhere from 1700-2100 sq ft.  I've looked at just about every prefab and stock plan site out there.  Since this is our first time to build we have a million questions and a somewhat limited budget.  If anyone on this site has experience in Oklahoma with a modern prefab or have worked with an Oklahoma builder to construct from a modern stock plan I would love to visit with you.  Just to give you an idea of what we are looking at here are a couple of websites we've been looking at: www.h-haus.com/index.html and www.lamidesign.com/plans/homepg.html

Look forward to hearing from you.