I have a 2014 JKR and I installed the RK stock mod 2.5". Same springs your looking at. Don't know what shocks your lookin at but I did the RK RRD.
At full droop my front DS hits both the exhaust and crossmember roughly same time due to angle, the rear doesn't hit but the angle is pretty extreme .
My new driveshafts will be here tomorrow.
So yes in my case I had to at least do front, I decided to do both.