I ordered a LR on 10/15, changed it to MR via email at 1am on 10/19, then forced the change myself via backdoor edit link at 10am.
So if I'd have stuck to LR I would have definitely gotten a delivery date by now. If I wouldn't have went white seats (the main reason we decided to change, trading 50miles of range for black-->white, black-->white, 18"-->19" for just $500 more), I likely would have received a delivery date at this point, per the spreadsheet. I can't help but make thing worse at every step!
Now I regret changing anything, but especially the white interior. If I get it before the end of the year it'll be worth it, but if I don't, I'll have to cancel my order and probably wait almost a year for a SR. Being a realtor, the tax credit literally means keeping $7,500 in cash in my bank account immediately, which I plan to use for the first year's payments while I continue to save up. I plan to always have a year of payments available, and pay off chunks of the car as I get big commissions.
I'm in the midwest, so my 6 week estimate would mean delivery by 12/1, and according to the spreadsheet, typical VIN to delivery time to Indiana is 14 days, so if I don't see movement on white seats being produced in the next week or so, I'm going to attempt to get matched with an inventory car, either LR or MR, or attempt to change to black interior MR.