Help pricing

[super6Guy]

I am "paying it forward" for a friend. He can longer drive his 08 E-92 M3. He has a degenerative spinal disease and is going in for his 4th surgery. He has to see his dream car go to a new home where it will be loved and treated right.

In my opinion it is a beautiful car with carbon fiber accents. Silver Metallic is the color. Interior is unbelievable. It looks like no one sat in the back seat.

My question is how do I price it? I have looked at Hagerty Valuation tool, the web and Bring a Trailer. The prices are all over the board.

What is the best pricing source?

Thank you!