Just got my '17 GT PP back from the shop where they installed BMR's IRS cradle lockout as well as the Progressive springs from Steeda. So far so very, very good... The ride feels much "flatter" for lack of a better word (a lot closer to my '13 BRZ but without the ride bumpiness). No wheel hop on my one test peeling off at the light, entering the freeway (where I used to get it all the time). The springs also greatly reduced the nose dive on hard braking making me feel a lot more in touch with the car. And, most importantly, I'm easily clearing my driveway bump as well as every speed bump I encountered since!
Note that the install was apparently trickier than anticipated since they had to order some hardware directly from Ford to replace some one-time-use bolts, nuts, etc that were holding the stock parts.