Also there are some who are considerably more sensetive to ecstasy then others.. the LD50 may be fairly high, however im assuming the LD1 could be noticably lower. Also through my knowledge it wasn't proven she only took 1/2 a pill, it is just what her friends said. IMO i know some people who would lie about there dosage just so that they didn't "as crazy" as say 8 pills. but also this would be serious times and its more likely then not they told the truth, im just suggesting.
but think back to when you were young and the police, parents, etc asked how many drinks you'd have, you'd try to make the dose sound lower.
Sorry about going off topic
I pretty much agree with what most others said, its not really worth the risks.. would you buy any other drug with unknown contents as apposed to say "pharmecutical grade".
Its up to you though, people risk there lives all the time with different drugs, but would you purposely take the choice with higher risks associated?