For custom paint, get black. Most of the custom painted GM show cars start out down the line as black. White would stand out quite a bit under the hood, and under the car. With black you can leave a lot of areas black and most people would never even realize the complete color was changed. It's a huge cost saver not to take the engine out and paint the engine compartment and just leave it black under there.
Order a 1LE up as black with hood vinyl deleted. Then repaint the car SGM, paint the hood flat black. You'd have a one of a kind SGM 1LE, wife approved.