Originally Posted by
dergside
I'm with JohnH's way of thinking. Looking just at the fuel costs is ignoring the elephant in the room in the circumstances of doing 40k miles a year. Depreciation.
With a 5 year ownership at 40k per year you may assume that a single car will have close to zero residual value by the end of term, so if you can find a way to manage that then you can consider separating business from pleasure, and maybe end up with cars that are each more appropriate to the specific use type.
Lets face it, for all the diesel downsides, 40k per year of motorway munching is the raison d'etre of exec diesels. Wear and tear is low because the car spends most of its time running reasonably steadily at optimum temperatures, etc., so the chances of it surviving 200k without major mechanical failures or catastrophies are good. Run on cruise control a decent amount and the economy is particularly good. This kind of driving is a chore and provides relatively little opportunity for "enjoyment" of the act of driving, so I imagine that getting in to anything half interesting will feel less special and less interesting a year or two down the line than it would be if it was a weekend toy that acts as an antidote to the daily slog driving, so focus on sourcing the optimal mile muncher for this purpose and this allows your toy to be far more focused on what a toy should give you, goosebumps when you walk out to it on a Saturday morning and plip the key at it. Whether that's an Mx or something a little less manic that is tweaked and modified to make it fit your pleasure needs like a glove, there are lots of options that don't need to be compromised by the need to not break your spirit after a couple of years of the daily slog.
If I get a bit of time later I'll see if I can offer a couple of practical examples to support my thinking.
Nice dilemma by the way :).