So: thought you might like to know that it's a much more worthy successor to the 406 than is the 407. The 407 would make more sense baged as a Citroen it's so strange. (Although I do like a big strange French car.)
The build and materials on the 508 are also a lot better -- frankly the 407 is embarrassing. Otherwise I'm still in the 407 and very happy there. (Although all the rubber in all the suspension is kackered and it's started signalling that it would like a third flywheel.)
I had intimated that there might be, say £1500, to spend on something fun like a v6 407, and thus I was coerced into spending £4500 on swapping the bastard 307 from hell. A good outcome, but it's dry bread and pull it for the forseeable for me.
I thought the arrangement was that I'd take it out once in a while in order to keep the DPF clean, but I have since been forbidden from using it. Have had to 'upgrade' from pp2k to diabox in order to monitor the DPF. Have found that a regen triggers at 71% soot load rather than the 67% on the 407. It had got up to 65% so I took it up the motorway yesrerday evening to do a regen -- which it did -- and I hardly noticed it. Very different to the 407 that goes down on power, growls, and drinks diesel. They'd obviously improved the system on the 407 a lot since their experiment on the 406, and I guess it's all moved on again. Excaust hit 560 degrees compared to 500 on the 407.
This 508 is an "SR" which, it tunrs out, means "poverty spec". No: auto wipers, auto lights, puddle lights, folding mirrors, parking sensors all of which the 407 has, and even the 307 had. The overtly plastic steering wheel is really horrid, not being circular feels awkward, and I'm not a fan of buttons on the steering wheel because they move so you don't know where they are. They're also more difficult to use compared to the two stubby stalks (3 buttons on 2 hands to turn on the cruise compared to flicking the thumbwheel and one button).
The engine is the 2.0 140. It's astonishingly efficient (although swmbo still manages under 40 on the supermarket run where I do 60). It also feels really slow compared to the 407 (2.2 170). If (like I used to) you drive a HDi 90 then you'll be right at home: nothing until 1800 and out of puff at 3000.