Insofar it appears Kepler cards aren’t softmoddable, or nobody found out how yet.
The Fermi gen was already so more miss than hit nobody really bothered.
When you read softmodding, you either read old stuff, or people modding later bought 8800s and 260s and stuff like that.
That is, turning a geforce card into a quadro by reflashing the bios, and make it show up as a quadro to install the respective drivers.
There is also the option of INF hacks to install a quadro driver that will run on geforce cards, but again, it seems not so successful, and pointless when it succeeds, on recent gens.
I haven’t seen hacked INFs in almost a year now.