i call it now, Thanks me later :)
https://en.wikipedia.org/wiki/Comparison_of_Indonesian_and_Standard_Malay
https://en.wikipedia.org/wiki/Comparison_of_Portuguese_and_Spanish
"Indonesian and Malaysian Malay are two standardised varieties of the Malay language,"
I think the fair comparaison is Indo and Malay is as mush different as Spanish and Latam Spanish
Language and phonology are one of my specific interest, I love speak about that.
Don't worry im' not saying that Malay from Malaisya is the main language and Indonesia is the sublanguage of Malasian malay.
I'm saying that Malay is a language with 2 stadard, one from MYSG and one from ID, none of them is above the other (The problem here is that Malay have 2 sense, and can refer to the language of ID-MY-SG or only Malay for Malasya
Quoting wiki "Indonesian and Malaysian Malay are two standardised varieties of the Malay language,"
https://en.wikipedia.org/wiki/Comparison_of_Indonesian_and_Standard_Malay
I'm sure you would also be able to have a full conversation with a Malay with your native language ^^
Sure some word will differ, they will have some exception and some expression that would make no sense to you, but, overally the 2 dialect are really mutually intelligible ^^