They stated at the launch it would be under $100k.
The car runs a 9 quarter mile. It is faster than a P100D by a significant margin. Im sure the P100D is faster 0-10,20,30,40,50 and maybe even 60, but if you ask which car is faster fullstop? The Demon is a faster car. Undoubtably.
The 'banned by the NHRA' is just a marketing thing. You can still take this car to the track. If you want to fit the skinny wheels, then yes, you'll need a cage/chute. But very few people will do this. The Mclaren P1 and Porsche 918 also run in the 9's. I don't see a big woohaa about them being banned from the strip.