MDMA can definitely be chased off foil. Done it many a-time. Rush is brief but not all that fiendy. Mostly a waste of time and MDMA to be honest. But doable if ya like experimentation. Works a fuckin' treat for peev comedowns though - by
far the best remedy
As for IV phet, it's the dog's. If snorting or bombing seems to have more of a rush you just ain't shooting enough or have shite IV technique and are missing more than you're hitting
As Blondin said, IV is more or less always the most effective ROA for more or less any drug by definition (certain pro-drugs excepted). If it's all from the same batch and doses are equivalent then you just don't happen to prefer the IV rush to the alternate ROAs. YMMV kinda thang.
To be honest, I never really rated the IV rush for phet unless it was properly good phet. And I do mean properly good. Even halfway decent phet can do the trick bombed or sniffed but won't touch the sides IV'd. Quality is everything. Well... quality and quantity. And technique. Quality, quantity and technique. That's it. What did the Romans ever do for us?