Considering the likelihood that any pill you buy on the street may be methamphetamine, the studies still contain some important information.
What's more dangerous: MDMA or the black market that sells kids meth pills and PMA labeled as MDMA? If you don't realize how much misrepresentation goes on, take a look at the pill results. You can even search to see what was tested from your neck of the woods. Kinda disturbing to see things like PCP in the results tho.
http://www.ecstasydata.org/