Forum newbie, looking into things before buying

[stefan2m]

Hello everyone, new to the site and didn’t notice a specific introduction forum... so here it goes!
I’m Stefan, 36yo father of 2 boys together with my wife and we live in the north of The Netherlands.
I currently own an E61 and am tired of it, I’m very tall so I was looking into an 07-10 Audi A6 Allroad tdi to replace it, as I thought an X5 would be too expensive to keep on the road; after some digging, it’s just a matter of tens of euros, not hundreds.
So... I’d rather have an E70 3.0sd/35d and that’s why I’m here.
Having owned something like 7 or 8 BMW’s prior to my E61 I have a general understanding of things to look out for.
What I am mainly looking for is fuel ‘economy’, and how long a set of tires will last.
I am looking at the 3.0sd/35d without sports suspension and preferably 19” wheels; I expect 24-25mpg (US) and about 10,000 miles out of a set of 255/50-19 summer tires (non rft non uhp, with all joints/bushings in good order and a proper alignment) and 8,000 miles from a set of 255/55-18 all weathers (we have moderate winters that are mostly just very wet, so proper winter tires are not needed).
Looking forward to hearing(/reading) some of your experiences!