Not sure how customs clearance works in an I->D transit scenario. I do know checking through on MH I->D is doable, where no bags get picked up at KUL itself.

It’s been a while since I did this with checked luggage, though, so I might be misremembering; I try to go carry-on only as much as possible, even if my bag is a kilo or so overweight… the additional J allowance can also help.

(Note so it’s clear for anyone else reading this at a later date: MH and Batik flights depart from KLIA T1 Domestic, so I->D transit is possible if flying I into T1; AirAsia departs from klia2, and requires exiting KLIA T1 altogether.)