I think donewitit answered all the questions. Softliss is econ. and has good reviews here. If your hair is weak, I would spend some time working on strengthening it first with reconstructors, and getting in good moisture before attempting BKT. Also, please, please, go back and read my post on the heat requirements of BKT. THis only applies if you have a good flat iron that states it has some sort of heat stability technology. You don't want to make your porosity problems worse with breakage.
Keep reading and wait on it before you make your decision. This will not make your hair "straight" on its own, and if you have no curl pattern, it may only help in the detangling process, but not much in the way of helping with curl def, or puffiness, natural "frizziness" that comes from no curl pattern.