Is it possible to have my local Ford dealer install the
Selectable Electronic Power Assist Steering (EPAS) Feature on my 2011 model year V6 Mustang? Also, how about having them install sport mode off the PP equipped V6's?

 

I doubt any dealer will know how or would risk getting blamed for voiding your warranty. I suspect it would be something tuners could do if they had an incentive (enough demand). All the hardware is in the car already. But steering can't be selected separately; if a 2011 Mustang has a sport mode (such as the PP), it also sets the steering to sport mode when you select sport mode. If a tuner made this available to all cars, it would probably have the same issues, i.e no mechanism to set the steering separately (switch or electronic user interface), so it could be there but like it is in the 2011 PPs.