Hi there, I make kefir yoghurt a couple of times a week. All you need is to buy the starter sachet or to get a few tablespoons of some already cultured kefir from a nice person. It doesn't need heating like normal yoghurt, I literally just put a few spoons of the last batch in a jar, add some lovely raw, organic milk and leave it in the airing cupboard for 2 days. It is a very tangy and slightly curdled looking result but I mix mine with stewed fruit to sweeten it at serving. I also strain a lot of the whey off mine to make it thicker. (then I use some of the whey in my tmx mayo to make it keep longer)
Normal kefir (not kefir yoghurt) doesn't need heating either, you just have to have the kefir grains to culture it with. These need to be fed regularly to keep them active or you can freeze them and use them at a later date. I 'killed/starved' mine accidently when I went into labour earlier than expected with my bub - need to track down some more from somewhere. It makes more of a thick milky liquid rather than the more textured kefir yoghurt. Makes nice smoothies etc...
So as much I love to use my TMX for everything, you don't actually need it for kefir!