Currently own a 2009 1.6 tivct focus. Thinking of changing to a 2017 St line. Plenty about with the 1.0 ecoboost And not so many 1.5tdci. We used to have a diesel before the 1.6 tivct and it was amazing on fuel, whereas the 1.6 is dreadful. We get low 30s. I don't do massive mileage, probably off put by going far due to the current car. Local garage has a 1.5tdci 2017 plate with 4900 miles on the clock. Looks really nice but not sure if I would encounter dpf problems etc in the future. I don't drive like a granny, foot down fairly often. Which engine is best out of the 1.0 ecoboost And the 1.5 tdci? 

Also what tax would I pay, this chart has confused me 

The tax rate will depend on when in 2017 the car was registered. 

For the 1.5 tdci with <100g/km co2, cars registered after the 1st of April 2017 would have £120 road fund for the first 12 months and then a flat rate of £140 after that. If it was registered before March 31st then it would be zero for the foreseeable future.

I don’t know what the emissions level is for the 1.0 but again after 1st April 2017 you would be looking at £140. Before then you’d be looking at probably £20 I would guess, depending on the emissions.

So you’ll either be paying £0, £20 or £140.

I hope I’ve got all that correct.