A Luta Continua - My Merc E class

Has your wife met Espadrille? Similar lack of logic to the car ownership problem. You'll never win.

On to the chosen cars...

Volvo - pricey for its age but low mileage.

Passat - looks lovely but DSG? Especially at those miles...

Honda - if it looks dodgy it is. Plus that wood trim on the centre console is just gross....

If she wants a clean car, it has to be a modern one. Old petrol engines will be as filthy as old diesels - just a different kind of filth.

You mentioned fuel efficiency but an old (15 years old, in that Volvo) petrol engine will chuck out more than CO₂ and water vapour. Why not at least try a reasoned argument for saving towards something modern enough to be clean in a year or two?

Only £600 more than the Volvo and 5 years newer: average mileage for the year which could be more healthy than too low a mileage. And it's an Aero - must be worth a look.

The Saab apparently has 207hp but still takes 8.6s to reach 62. What can that automatic be doing to it?

This Volvo manages the same from only 170hp, and isn't as - well - nasty as the last GM-wrecked 9-3s became.
www.autotrader.co.uk/classified/advert/201801303226977?make=VOLVO%26model=V50%26utm_source=Email_a_Friend%26utm_medium=Email%26utm_campaign=Email_a_friend_car

Since you are - how shall I put this? - not a family whose motto is 'mind your head', you should be fine with the space in a V50 - not that it loses out much to the V70 anyway.

It's still a ten-year-old car, though.

I confess I've not driven one, but you could feel the GM accountants biting by 2008. Remember that I had the previous, hatchback 9-3, which did a good job of hiding its GM ancestry, especially inside. The 2003 car got off on the wrong foot by using a semicircular speedometer; those were last seen in Vauxhalls of the 1990s and ate just wrong. Then there was a facelift around 2006 that just made it look and feel more even more low-rent Vauxhall, rather than proper Swedish Saab.

The last one I rode in was a station taxi. Compared with an E220 of similar age, it felt ready to fall apart.