Next mod, adding a bulkhead/ cargo barrier. These can be factory ordered, but the factory barriers are steel, the window is small and the inside isn't lined.
I ordered a Motexion fibreglass bulkhead. Had I known it was fibreglass I might not have got it, I was expecting ABS like the one in my T5. I think they're all ABS now though.
A big van means a lot of air to cool, so the A/C has to work hard. Reducing A/C use is a definite ecomod since around 1l/100km goes into running the A/C in summer. Other benefits include safety, and noise reduction, plus potentially more storage space if you hang things off it. You'll also never have to use the rear window demister.
View from inside:
View from cargo side: