If you got the 4C emitter in the S2+, you don’t need to do anything, at least not to the emitter. 
Get a 20mm TIR lens in whatever spread you want (60° for flood, 5°/8°/10° for spot), and just replace the reflector with that. Beautiful tint, your choice of beam, all the colors are mixed so nicely, no fried-egg beam (yellow in the center, blue at the edges) because of the reflector.
TIRs rule…