I've been tweaking my Novatouch for quite some time, and I've finally gotten it to be almost as enjoyable to type on as my silenced RF87UB55. My modifications include the following:
+ Silencing Rings
+ Lubed stabilizers
+ Self-adhesive foam squares under the spacebar
+ Ducky PBT keycaps in OEM profile
The silencing rings substantially attenuated the return-stroke clack noise, and lubing the stabilizers and putting foam pads under the spacebar greatly attenuated stabilizer rattle.
I've tried a number of other keycap sets, including stock, SP ABS double-shots, Originative ABS double-shots, Imsto dye-sub PBT, Leopold PBT, Vortex PBT double-shots, and Ducky PBT in OEM profile. I found that Cherry and Leopold profile produced contact noise on the downstroke; this was almost eliminated by using the higher OEM profile.