Two things: 1. Replacing your reproductive bits, your man or womanhood with metal, plastic and motors is fundamentally going to disconnect you from humanity more. 2. Lowering PDS cost of limbs was about making it easier to fit a cyber limb into your PDS load, reducing the drive to just off your character when you lose a limb. Where we want a lot of folks having cyber limbs, we don't really want the majority of folks replacing their junk. We'd rather have it be more special if you decide to do that. :)