Is it possible to well integrate MPS based DSL other IntelliJ IDEs like PhpStorm?
Most wanted features are handling files by its types (*.ext pattern) and PHP files generation (transparent or at least automatic).
MPS is usable in a restricted form in other IntelliJ platform based IDEs, like WebStorm, PhpStorm. I don't know of any special support for generating PHP code via MPS, at least MPS team hasn't done it for sure. Also, answering the question from comments, it is correct to say that programs in DSLs implemented in MPS are by default persisted as xml files. Custom persistence can be implemented as a plugin to MPS. Also, custom persistence can be tailored to a particular DSL, unlike the default xml persistence which is language agnostic.