A twin-turbo 3.2-liter flat-six engine mated to a six-speed H-pattern gearbox, brilliant yellow paint, full leather interior (with Recaro racing seats), carbon disc brakes, and a rich winning history at Le Mans also come with the car. According to the seller, this is thought to be the only yellow example built.
As rare as the road-going 911 GT1s are, they do come up for sale occasionally, including a silver example in 2012 and a white one in 2011. The car sold in 2012 was listed at $2,325,000; in 2011 the white car listed at $1,700,000.
There's no price listed on this yellow example, but you can find more details and images of the car at the official sale listing on Trofeo Cars.