emtae001
From what I know, you can change whatever option you want until you get to 3000 level without adding any delay to your built. At 3000, your order is firm and options can no longer be changed. In my case, I ordered the STI option (rocker panel extension) which are now on constrain as per Wednesday. I then asked my dealer to cancel them as I did not want to add any delay into the manufacturing process by putting the production on hold waiting for the rocker panel to become back in stock. He told me that at the 3000 level he can't change anything so there are 2 options. First, as the production team has accepted the car into production, they may have secured the rocker panel extension and the car will have the option (installed by the dealer). Second, they know that they will not have the rocket panel so the car will be manufactured and shipped without it and GM will update the invoice to the dealer accordingly. If this is the case then my dealer will place an order for the rocker panel through the parts department and I will get them whenever they become available in the future.