I spoke to my accountant.
This type of donation is what the IRS deems as a "Quid Pro Quo" contribution. Under IRC Section 170, the amount of deduction a taxpayer can claim is reduced by the value of goods or services received. In my above example, your actual donation is $2m.
The charitable donations of cash are limited to 50% of your "Adjusted Gross Income" in a particular year. In my example above, if the AGI is 1.4m. one could only deduct $750k of the 2m charitable donation in the first year. The excess contributions are carried over to the succeeding next five years.
However, the actual tax savings associated with the deduction are based on your tax rate for both Fed and state. For simplicity, if your combined tax rate is 50%, you save $375k in taxes the first year ($750k x 50%). All things remaining the same with your AGI each year, you continue to save $375k in tax, until you reach 50% of your charitable contribution = $1m in total tax savings for your $2m contribution.
Bottom line, you donate 2m, you get 1m back over time (up to 5 years). In my above example, if I paid $2,468,000 for the car, my actual cost would be $1,468.000.