From a logical point of view, I think its better to keep the 36 la. Its a late model 36 meaning that it should have most of the early 36 issues sorted out and parts are cheaper and seemingly more robust on the 36. Also depreciation for the 36 has stabilized somewhat, while the 46 will continue to drop like a rock till it probably hits Rm80k or so in a few years time..
Of course if $$$ is not the main issue, then the 46 should be a nicer car to own, more comfy and not as dated for now..