I don't know if the silencer will do any help. I have BC coilovers which is almost the same stuff as Megan. Without any silencer put on, they don't make any sound. I have read in this CL that, in most cases, the infamous Cluncking sound is caused by the shock internal which can be cured by changing a new shock cartridge. Tein silencer is for prevention of the noise causes by coil binding (coils hitting each other during a full compress of spring). If the preload of the coil is set correctly, I don't think we will have coil binding problem with Megan/BC coilovers.
But, anyway, it should be better if we have those silencers on. Problem is we might add unnecessary cost to the system. How much does each ring cost?