The additional height of the Sidepod should allow more air to move around the undercut to the rear of the car. Meanwhile the frontal height of the Sidepod being increased has also required the team to make alterations to the sloped section of bodywork that trails down to the exhaust channel. With approximately 50-60mm higher Sidepods the team may be finding that their previous 'Coanda' approach isn't as planned even though the team have also shortened the overhang at the rear of the car. This is in contrast to Ferrari and Mercedes who have both re-orientated and lowered the section of overhanging bodywork at the rear of the car. Which leads me to believe that the team are drawing the exhaust plume down onto the floor much further back otherwise the airflow coming from around the Sidepod will impinge on this.
The MP4-28's rear wing is also pretty much a carry over when compared to it's predecessor and although Melbourne is a circuit requiring a good level of downforce I was surprised to see how much Angle of Attack (AoA) the team seemed to be running combined with a Gurney tab too. In terms of Rear Wing design Ferrari have to go down as the team with the largest update over the past few seasons when they introduced their Trailing Edge Slats. However an area that seems to have passed McLaren by whilst others have taken advantage is the use of the Top Flap V grooves used to reduce drag. Meanwhile further down the car the team are still running very much the same Beam Wing and Monkey Seat configuration they ran last season too which of course is allied to the effects of the Diffuser and Rear Wing so all must have changes made in harmony, it's just perplexing that not much progress has been made in the area.