We could probably do with a seperate thread dedicated to this stuff, but its my opinion that spending a 5 figure sum on a car to ensure the monthly running cost are as low as possible is misguided. If you wish to reduce the cost of owning a car surely a better way to do it is to spend less in the first place.
Lets just take one example, we'll use made up figures as an example. We'll pick the VW Golf.
You could buy an 09 VW Golf 1.4 for £13,000 because you want 'low running costs'. The 1.4 isn't a great engine, infact its terrible (Assume no twincharged version) and its woefully underpowered for the car, which itself is a low end base model. But its 'cheap to run'.
Or you could just spend less in the first place - perhaps £10,000 on an 08 plate 1.6 Golf. Not a performance powerhouse, but an engine more suited to the car. Marginally higher running costs, but nothing to write home about.
Then 3 years later, you'll probably find you've lost less money in depreciation on the 1.6 than you would have done had you preceeded with the 1.4 purchase.
I just personally find the concept of spending 5 figure sums on cars - by anyones standard this is a LOT of money - and trying to save every last penny on running costs - rather contradictory.
It's not as if 4 figure sums don't buy very, very good cars if saving money is your primary goal.