I just ordered an 05 GT- the side airbags are NOT a required option with the Premium Model/Interior Upgrade package. So- I didn't.
BTW: 05 GT Premium, Interior Upgrade, Dark Charcoal leather, Alarm System, Standard Wheels, locking lugs, color accent (red seats, etc), Shaker 500, Manual Trans: $ 25341 X-Plan. They are telling me "maybe" by December 15; if not- January after shutdown.