I note your advice to hit 4500 rpm through the gears several times a week. Does this apply to all engines? At only 4000 rpm in my 2008 Citroen C5 2.0HDI I'm doing 40 mph in second gear and 65-70 mph in third. It isn't easy to find a stretch of road where it's always feasible to reach 4000 rpm in those gears, and still less in fourth, fifth, or sixth, and 4500 is where the red section starts on my rev counter.