You drive in the country not busy roads Saggy. You jam your foot down on a roundabout for an emergency stop, stop start then stops the car, your then compromised when you pull away. It's crazy. If you drive like a pensioner at 30 mph you are fine but certainly not in the south of England with SS in a DSG.
Simp, you need Android with Blutooth, a wifi connection or 3g / 4g. You download the app and you can buy it from there you need the pro activation key else you can't do the fancy stuff and the ring pull is handy to pull it out after use. I just push it in place by touch now and pull it out on the ring key. It does all VW cars. You don't leave it in else it keeps all of the cars systems live and will flatten the battery, they do, not the dongle. You use it with the car running.
It was about £60 at Xmas don't know what offers they have at the minute but you do need the pro.