If you've decided that you just can't do without a diesel Focus, Ford has quite a range to choose from. Along with all the different trim levels and body styles, there are three versions of the TDCi turbo diesel engine, which comes in 1.6, 1.8 and 2.0 formats.The car tested here is the Zetec five-door with the two-litre engine. This makes it virtually identical to the 1.8 TDCi which was the subject of a road test a few weeks ago. When I was driving that car I reckoned that the 1.8 was a decent enough unit, even though you would be financially far better off choosing a 1.6 instead.It follows that the 2.0 is an even less wise move if you're on a tight budget. All other things being equal, the bigger engine adds £550 to the list price (making a total of £17,545 in this case), insurance is in Group 10 rather than Group 7 for all the other diesels, and combined fuel economy suffers too.Mm. But there are other considerations. Although the 1.8 seemed perfectly okay at the time, there's something about the 2.0 engine which makes it seem better suited to the Focus. It produces a maximum of 133bhp, and while this isn't exactly tarmac-tearing stuff, it feels just about perfect for the job. The extra power means that you never feel you have to push the car hard (not in conventional everyday driving, anyway), but it's not so much that it strains a chassis which, despite the standard fitment of "sports" suspension to the Zetec, never feels all that sporty.I'm not greatly fussed about that suspension in the 1.8, since it adds a certain amount of jiggle to what is otherwise a high-quality ride. In the 2.0 (for whatever reason - perhaps a slightly different set-up, though it's difficult to tell) the ride is good for more of the time, and front-end jarring is reduced to a minimum.What with all that, it isn't long before you start trying to convince yourself that the 2.0 isn't the wallet-shredder it at first appears to be in comparison with other Focus diesels. You can't do much about the insurance, but £550 on the list price isn't a particularly big premium. And if you go easy on the power, using it only when you really have to, you can assure yourself that you're using less fuel than someone who drives a 1.6 or 1.8 hard all the time.As for the related issue of CO2 emissions, the 2.0 produces 144g/km of the stuff. That's a little more than the 137g/km officially ascribed to the 1.8, but it still leaves the 2.0 in the same VED grouping (Band C - £115 annually, rising to £120 from April 2008) so you won't pay any more tax. You would have to opt for the much slower 1.6 to drop into £35-per-year Band B territory.I think I've done it. I think I've convinced myself that a 2.0 TDCi would be close enough to costing the same to run as a 1.8 that I'd go for it every time. That's assuming that I'd want a Focus in the first place. There are a couple of niggles: first, the handbrake, which has been so obviously placed to be convenient for the driver in a left-hand drive cabin, is more awkward to reach in a UK-spec car.Second, rear visibility is terrible. Paying extra for rear parking sensors would be a wise investment, and could well mean that you avoid having to cough up a great deal more for body repairs, but it still doesn't entirely solve the problem.Set against these things are the splendid suitability of the two-litre engine and the very impressive levels of comfort, most of the credit for which goes to the truly excellent seats. Yes, there may be aspects of the Focus which annoy me, but on the whole it's a car I could imagine living with for a long time. Engine 1997 cc, 4 cylinders Power 136 bhp @4000 rpm Torque 236 ib/ft @2000 rpm Transmission 6 speed manual Fuel/CO2 51.3 mpg / 144 g/km Acceleration 0-62mph: 9.3sec Top speed 126 mph Price From £17791.00 approx Release date 01/01/2008