To start off with, here is a link I got from using our search feature. I just typed in "silicone" and got lots of topic threads. http://121380.activeboard.com/t17805675/silicone-babies/?r=325178 Also, in specific answer to your question... with silicone babies, they have a totally different feel, and their parts weigh more (as in the "solid" silicone). You cannot sucessfully use heat set paints on them so you will need a whole new set of paints. There are paints made specifically for the silicones and I believe there are a few different types depending on the silicone. So far I haven't seen any straight silicone kits, they are usually full dolls already. You also cannot bake them as the silicone sends off toxic fumes.
I hope this gives you some insight into silicones. Best advice is to "search".