@The Panda Nut
TA.
I do know the brake disc/rear suspension setup is entirely different - my 2006 169 4x4 had all new discs fitted after nearly 10 years (I had it for 14+ years) and my “new” 2016 312/9 TA 4x4 recently had the same job done. Was expecting simple job+reasonable price, and I suspect my local independent was too! (who I’ve used 40+ years) - instead he had a nightmare job: completely different rear and very awkward.
Also, the 169 had a simple mechanical 4x4 system (which was 100% reliable - because nothing to go wrong?) but the 312/9 is ECU controlled (bit like Haldex?)
I suspect the clutch/DMF setup is very different too (not sure 169 had a DMF…?)
But I think you may be right about the body frame - the doors+sills are the same? (maybe the tops are different? pretty sure the fancy sill protectors I’ve just fitted had the same part number as the 169)
And then, of course, there’s the engine…


Btw the Haynes ‘thing’ is currently on offer at £27 and the blurb says it includes an OBD “diagnostic tool - Enter a fault code in the electronic diagnosis module and follow the instructions to test components in order, and establish the likely cause of a problem. Our tool goes far beyond what commonly available fault code readers offer, and puts you, the car owner, back in control. Even if you choose not to complete the repair yourself, you will know exactly what the problem is when you hand it over to a workshop.”
BUT BUT BUT this ‘thing’ is only available from the cloud online so cannot be downloaded! So you’re working outside in the rain and your router connection keeps dropping out…

AND they say it’s no longer hold-your-hand step-by-step guidance