Seems to drive fine and maybe a bit smoother on the changes, though I have to say that the oil that came out was pretty clean, which I suppose it should be after only 24,000 miles, even if it is 11 years old.
Next job was to change spark plugs. Sadly, in a senior moment, I had bought plugs for a Xantia V6 which are not the same as those for a C5.
Worse was the fact that I had already removed the inlet manifold before I discovered my mistake. 
Still, it gave me the opportunity to clean the small amount of gum that had deposited in the throttle body.I also have a fuel filter to fit but I can't find where it might be located, if indeed it has one. It is listed as a replacement part at GSF so I ordered one without checking first where it might be located. All references in the manuals appear to indicate it might be an optional fitment according to country, which seems a bit strange to me. Can anyone confirm this?
Another little problem that I spotted while crawling about was the central exhaust joint is a tad corroded and loose. Same spot where it happens on the Xantia at the centre box, so I will have to attend to that a bit sharpish before it falls apart.
