Value of Sport Seats

[2002Silver4.6is]

I have a full set of sport seats (front and rear), brand new, that I want to sell but I have no idea of what price to ask. From BMW the front seats are $4,000 each!! They are the grainy leather that is different than the smooth leather that is in my 4.6is. They really are beautiful. I picked them up with then intent of replacing my 5 year old interior but have decided to sell them.

Is the rear sport seat any different than a regular back seat? Where would a part number be located on them?

Anyone know what to ask for them (front and rear)???

Appreciate the advice!!