On a serious note, you can wait for aftermarket springs to show up (specific to the RS) but there's a chance what's already on the market for the ST can work in the RS's factory coilover tower.
Well the Focus RS Rallycross uses a SLA-type arrangement joined by 3-way adjustable Reiger dampers front and rear. Maybe you can find something similar to what they use?
There are several aftermarket spring, spring/shock, and coil over set-ups already here for the RS. Many lower from .7" to 1" in the front, and 1" in the rear. I go do CJ Ponyparts site all the time, drool, and make a wish list! I had the KW V3 Coilovers on my 2014 Fiesta ST, and they were GREAT, but I had NO idea how and where to set all those potential damping/rebound knobs!! For the RS, KW also makes a set of coilovers that allows us to KEEP the ride settings (N/S/T/Drift) as well, and they have the largest potential to raise or lower the car! GOOD LUCK figuring out where to set the shocks. Also, EXPENSIVE: $3300+!