You're probably right. I just tried to dig up the article I had read (it was sometime in late 2012), but all I could find were speculations. I did, however, find multiple sources that said the IRS was going to increase cost (for Ford) by $100 per car when they considered it years ago, so $200 increase for the customer seems reasonable. Maybe it would be a little higher, but probably not $2,000.
The only thing that might make that $200 significantly higher is the fact that the power increases we've seen in all of the engines might require sturdier parts throughout the drivetrain/suspension to account for the loss of the SRA. But again, this is all speculation. I'm not an automotive engineer (or any engineer for that matter), so I have no idea what's required to put 500+ HP down to the ground safely and reliably.
2014 GT Coupe, 3.73 gears, Security Pkg