The iPhone (much like many laptop options) needs a swipe, where the A8 one is a full finger pad read, but is really easily affected by angle, and pressure used.

My wife always gets in and starts the car in the morning and does the preflight checks such as heated seats and windows and entering destination.
I would hate the seats and everything to move to her position. The memory positions are stored with the Key ID at the moment would this be totally redundant if Fingerprint ID is fitted?

It would, yes... Assuming the thing works every time.. Car will always start if it can find the key as the fingerprint is user ID only, not security.

...so where all this info would be stored if key is redundant after fitting fingerprint switch???

The key ID is not redundant with fingerprint sensor... the seat position etc. will be still adjusted based on the key ID. For the same reason I find the fingerprint sensor a bit pointless though ;)

...so if you have a fingerprint start button, can you start the car with the key without scanning your finger??
Cheers

Absolutely..

So whats the point to have it if data is kept on the key and fingerprint isn't required to start the car??
So stupid...

Well exactly... I wouldn't bother with the retrofit. The fingerprint ID does "override" the key ID with memory setting etc. so if you have more than 2 regular drivers it could be useful. In my case there are only 2 drivers, my other half has her key and I have mine.

This is why my Mrs has her own car ;)

I would rather be abused by Gorillas somewhere in the Vietnam jungle then give my 8 to Mrs...

Thanks for all the info guys +++