@Breezyracer; The beam wing is still an alternate part, it isnt integrated to the diffuser, though they are very close together, other teams have it too due to their positioning and of the position of the tunnels. What it does is simply the same as an gurney, it acts as an extension of the tunnel and helps extraction due to the lower pressure created by it too.
The upper is the new, lower the old. As you can see the beam wing and tunnel exit it simply related to each other, if you wan tit or not, the relation is there. The idea is similair of what they did in Group C, the twin tier rear wing, you had an lower deck wich was a few cm above the diffuser trailing edge, these decks were quite long and to maximum length. Then you had an upper tier wich was short chord due to the interfeirence of the upper and lower tiers.
Overall such an setup increased downforce by 18% for no increase in drag, and such an 18% is an huge number, of course due to the F1 cars nature this will be less, but it is still an reasonable amount that can be created by this. Next year it will all be different again, the beam wing will probably be run at maximum height to get as much clean air over it. But this all is way off topic.
OT: I think sidepods will just stay the same, though they will be ever going tighter and tighter, next generation sidepods will be depending on what engine will be run. The sidepods will be combining downsloping and an big coke bottle, also the engine cover as small as possible to get as much clean air to this section. Also the sidepod shapes will be much cleaner, so no holes in it for the exhaust etc. What we will see is an different position for the exhaust, probably as low as possible, also to help lowering the CofG wich will be even more important.