I am probably going to use Edmunds on-line and send my three local dealers the "chance" to bid on the M3-S. Question is whether to have them bid on the car and then give me a separate price for the DIO (ie. lip spoiler, wind deflector)? Seems like I would want to tell these dealers about the DIO up front so maybe they will "throw" in at reduced cost, in order to get the bid.
Any other suggestions about on-line bidding are welcomed.