Malaysia has two states (Sarawak and Sabah) on the island of Borneo. Here's the country in a standard Mercator projection.
If you want them on the same page, github.com/rveciana/d3-composite-projections has a projection written by Saiful Azfar Ramlee and Roger Veciana i Rovira.
Based on images from Department of Statistics Malaysia, a more "tip-to-tip" view. East Malaysia has more land area than Peninsular Malaysia. Both projections are downscaling it, but this one is 0.76 to the original's 0.615. There was a little discrepancy which makes me think that DOSM's East Malaysia is stretching the latitudes/y-axis a bit.
Based on more images from Department of Statistics Malaysia, with an angular divider. Better for portrait layout. East Malaysia is 0.8x scale of Peninsular Malaysia.