I have installed couple cheap universal accessories that are doing what they are supposed to do pretty beautifully
Got a sunglasses holder for AU$5 and a mobile holder/charger that goes into cigarette lighter port for AU$15. Though not an accessory, just to give some contrast around the radio/ac area I bought a chrome moulding trim for AU$3.50.
I also wanted to install BMW's centre console DVD system so I went above and beyond to finally make them say "ya it's available for Australia" as they initially just told me off. They asked around AU$2,300 for it but I was hoping to get it for $2000 but for some reason they don't seem to be showing interest about it and I'm tried of chasing it up. More importantly, I found this USB TV stick thing on computers, so have bought a head-rest tablet holder for my surface pro and the usb stick to watch movies and TV on the go
I only spend around AU$60 for the whole thing
. TV isn't usable while driving so at the moment looking around if upgrading antenna might help a bit.