Some of the 2017 RWD S's have the frame portions needed for a front motor... but you'd need to replace significant portions of the front suspension, wiring, junction box, LV wiring harness, etc in order to make it happen. Also, you must replace the rear motor also to do this, since there is no configuration of base-large-rear + front that exists. And since you have a large unit, you'd need to replace the entire HV wiring harness to switch from a large to a small rear motor for dual motor non-performance (compatible with all 2017 batteries), OR you'd have to put in a performance rear motor... AND, since you only have a RWD, which means you don't have a battery pack capable of AWD performance, you'd have to upgrade that as well to at least a 90 performance pack.... which would also mean upgrading the suspension all around. And this isn't even counting all of the reconfigurations/calibrations/etc required to make this all functional when complete.
TL;DR - Don't even bother. Sell your car, buy what you want.