Diesels give you the advantage of far better torque and therefore mid range performance, as well as better fuel economy. Petrol cars tend to be a bit quieter, so sound more refined. Diesels need to run at higher temperatures (I.e. motorways) and for decent length journeys regularly or can become problematic, whereas petrol cars are happier with lots of short journeys. I like diesels but they are only really of benefit if you do more than say 12,000 miles a year. With advancements in petrol engines in recent years, good petrol engines are now almost as economical as diesels used to be, so the economics are narrowing (unless you go for a petrol Volvo XC40 as some members are posting very poor mpg results on those). Motability seem to be hiking AP’s of diesels, which further tips the balance towards petrol. The Q3 is quite small as SUV’s go and, being an Audi, I would think is perfectly adequate with a 1.5 litre engine. Sounds to me as though you have made a wise choice.