My guess is that the euro amphet (always sulphate, for some reason, but what do i know) comes in two grades that come down to the chirality: the good base that gets u spun off a dime must be a high purity dexedrine, the weaker, average crap, aside from impurities et al, probably is a racemic one as well. That's what I read years ago on some EU/DEA primer, the P2P synth was king of the market but occasionally someone was making higher quality.
unquestionly tho pure d-meth is stronger but not pound for pound exactly. It lasts much longer, releases more serotonin. I think racemic meth is even still present in the american markets, depending on what chems the labs had in mexico at the time. there's been a few bags I've touched that were so bad they seemed like they would have been racemic. I've had tons of local shakenbake birch reduction tweak that was better than that stuff, and a pseudo-to-meth reduction produces only d-meth (well not to mention over-- and under-reacted product, unfiltered mutagenic ingrediants, disfiguring fireballs...but no levo-vix at least!)