To prevent the swivel mount moving so much, put a piece of plastic bag over the ball joint, then push together. The movement will be stiffer.

Why is this any better than just using your phone, bigger screen? Is that the only reason

A good start would be to remove all the crap hanging from your mirror and a potential to take someone out because you couldn’t see past all the danglies?

I’ve got one, bought from Aldi , I use it in a 2011 bmw that has no Bluetooth, so I use this screen and a Bluetooth adapter, had it a month and done 1000miles with it, and it’s brilliant, I use Waze , and Spotify and can use my phone to call perfectly.
I bought a longer aux cable than it came with, the aux is in the centre arm rest on my car and the cable that came with it wasn’t long enough.

I would use the CD player mount with a ball-socket and attache the ball part of the smart screen to it instead

This kinda reminds me of the 90s before I had my first CD-equipped car stereo. They had those weird audio adapters that would work via your cassette slot in the car - it was basically an audio-cassette-shaped piece of plastic with a cable coming off it. Insert that into the tape-slot, connect the cable to a 3.5mm outlet on whatever device you wanted to hook up and you could now listen to an AUX-device on a car-radio that didn't have an AUX-in. I used that to connect a Sony Discman which was powered via a plug for the cigarette lighter. The CD-player would sit on the passenger seat and a bunch cables was running between it and the radio and dashboard. It ... worked, sort of but it was such a mess visually and when I was trying to swap out a CD while driving (no MP3 CDs back then).
I think what I'm trying to say is that instead of spending ~€40 or so on something like this, I'd rather not spend any money or save and then spend 300 or 400 for the Android/CarPlay conversion-kit the manufacturer offers for my car. Just like I just should've swapped out the radio back then for one with a CD-player, a proper AUX-port or an input for a CD-changer.. :)

10:28 it’s horrible with all the wires

I have this product in my 2006 mk8 Honda Civic and it’s awesome! It fits perfectly right next to the radio and hvac display (off to the left of the display) with the solid stuck down base on perfectly flat panel and does not obstruct the windscreen at all because it’s below the windscreen… For the price, it’s really very good….

Those cables would drive me bonkers

I don’t know why but the dog cracks me up. Star of the show imo

I used a cd player adapter with a ball end to hold my screen, plugged it in and works perfectly. I also have a Fiat 500.

I bought a Car Tablet Pro Max for £75 for my camper.  I've taken it out as it's just as cheap to use a tablet with a decent launcher, you get more usability and it's more customisable

You need a mount that fits that factory dash mount then goes off to the left and down to set the display right beside the instrument binnacle.

I’m using a similar cheap CarPlay adapter. Since I mostly play audio from Spotify, I ordered a CD-slot phone mount for it. To make it work, I removed the original phone holder part from the mount and attached the CarPlay screen directly instead. It uses the same round ball joint as most phone holders, so it fit really easily. I just put the round support piece behind it and tightened everything up. Works pretty nicely and honestly turned out to be a good budget setup. I did this on an Alfa Romeo MiTo, so the setup is pretty similar to your Fiat 500.

Another option you may wish to consider
I attached a Quadlock Magnetic Universal adaptor to the back of my TomTom as I find their mounts are pretty rock solid.

Our aldi where I live never has anything like that, its poor with all middle isle specials and lidl is just as bad

Bin those damn air fresheners man!

I've got a carpuride & a cheap Amazon that both play over FM as my 21yr old car doesn't have an aux port. The carpuride is too big for daily use (my fault, I ordered the wrong one), the Amazon one is smaller and ok for daily. I only use either of them for trips, but that's because of my daily usage. Not tried either in the Calibra yet, but I envisage vision blocking which isn't an issue in the E61 as they both fit where the eDrive screen sits.

This also needs real world testing. Many of these types of units keep dropping out. Some drop the audio; some drop the connection. Give it a real-world test on the road.

I suppose you will only know how good they are in usage, will it cut out etc,lose signal,be interesting to hear what Ben's family member thinks of it.