First of all the coupe is $3,000 more then the four door. Plus there is alot of unnecessary options on that. ie extended leather,park distance control, hd radio, rear sunshade.
Take alot of those options a way and keep some that most would want like the premium package and all, and you get a nicely optioned 4 door for about 60-61k dollars.
edit: Plus a 2 door would have to be compared to the upcoming RS5 which i would think would be at least a $3,000 difference from the RS4.