the only size shiv that has lower stack than that 54 p5 is the XS(S is only 7mm lower, but aduro stack is more than going to cover that). so if you want to go lower up front as the reason for change, you will probably need a negative rise stem as well as the aduro has fairly low stack in your set up vs any other bar system out there

based on where your shifters are in the pic, it does not look like you want less reach, or else you would have taken care of that already by shortening or changing extensions and if you want same reach, then you need to make up 4.6cm of lost reach when you go to that xs shiv