Advice needed on bmw i8 coupe negotiations

Hi guys,

I managed to negotiate the i8 below with my local dealer at $1,150/month including Florida taxes ( 3 years, 10k miles/year, 7 MSDs, drive off the first month and MSDs the rest included in monthly payment) I don’t have yet the official quote to put the numbers in the calculator.

Not as good as deals in SoCal or up North but is OK for Florida (I think…)
I negotiated based on some offers in here and now they want me to show them a quote from a dealership. They don’t want to do anything until I show them that.
So I’m kinda stuck, the brokers in here are not willing to help with this (and its understandable)

Any advice?

Here is the car: