but you should also check the miles that your odometer measures .... :-)

A good point and one which many people don't think of, if your speedometer is optimistic by several percent why would the odometer not be the same.

We are on our 3rd VAG TSi now.

None have been a 2.0 but all are incredible good.

First was a Seat Leon 1.4 TSi 140 PS. It replaced a BMW 118D that averaged about 47 mpg over 5 years, the Seat averaged 46 mpg in the same use and on a run would do 52 mpg.

2nd is a Skkda Superb 1.4 TSi 150 PS. It replaced the Seat. Despite being much bigger its averaging about 45 mpg overall and on a holiday road trip we have seen as much as 55 mpg over 1000 miles. We had a Mondeo 2.0 TDCi some years ago, similar size to the Superb, similar performance but despite being a diesel it would only average in the high 30's and just touch 50 mpg on a road trip.

Wife now has a 1.0 TSi Skoda Fabia 110 PS. Its a similar size to the Mk 3 Golf TDi 90 PS she had some years ago but its much quicker. Overall its doing 50 mpg, on a run we have seen 60 mpg. Its only 4 months old so it will get better. The Golf averaged low 40's overall and would do about 56 mpg on a long run.

All the above are calculated. The Skodas dash displays are very close to the truth (about 1/2 a mpg in both cases) but the Seat read high and the VW Golf was a complete liar.

Just enjoy the Audi, we have never had it so good.

I suspect a lot of the discrpancies even between cars from the same make are due to the differences in tyre circumference - it may well be (for example) that a particular model in general is set up for 205/55 R16 tyres, but higher end models may be shod with lower profile 17in or 18in tyres, which by law can vary up to 2% in their rolling circumference from the original one that the car's odometer etc was calibrated on.

Whether makes do this for just one or representative wheel and tyre combos across a model range or every combination of wheel and tyre fitted when new, I'm not sure. I suspect the former.

In addition, as has been said, odometers , like speedos, are probably calibrated to slightly over-read and are also affected by the small variation due to tyre wear.

The brim-to-brim method is fine only if you use it on an overall total basis like I do, i.e. keep a running total of miles and fuel used up to your last fill up and calculate the mpg based on that alone. My Mazda3 1.6 petrol averages 40.5mpg over the year, varying from mid 30s in town/winter to as much as 46 on long runs in late spring or early autumn when the A/C or heater isn't required.

Mine gets higher than the HJ Real MPG figure because a) I'm a light-footed driver (not slow) and b) the vast majority (distance wise) of my driving is done on dual carriageways, motorways and fast-flowing single carriageway roads.

From reading up on the subject, and it appears that it affects some VAG petrol engines and mostly those earlier generation TSi/FSi engines, that significant improvements in mpg were, initially at least, at the expense of far heavier usage of oil - I remember seeing people write in to HJ's column and on the Good and Bad section of the reviews about such VAG turbo petrol cars regularly having to have oil top ups, some even every 1000 miles.

I believe John Cadogan has done a technical video on his YT site about what they did in this regard. I suspect that most of the more serious 'issues' regarding excessive oil use have now been resolved, as reports of such problems on the newer generation TSi engines seems to have reduced significantly. Its likely nowadays to be a small trade off (a small about, if any) of oil top ups required against 10%+ better mpg (as well as better responsiveness of the engine) than a N/A engine of equivalent performance.

Even if the OP's figures use the trip computer and its even 10% inaccurate (high), that would still mean they are achieving 38-39mpg, barely different to what I am in a smaller, lighter (100kg) car with a 1.6 N/A petrol engine that produces 30% higher CO2 emissions (test figures).

Admitedly VAG's TSi petrol engines are probably the best on mpg across turbo petrols (as they've been making such smaller capacity engines far longer than most other makes), blending both performance, mpg and low emissions (no defeat devices for them), Fords and Vauxhalls not so good on the mpg front with other makes in between.

It also shows progress in R&D that my old K11 (mid 90s) Nissan Micra 1.0 petrol had a listed ave. mpg of about 47mpg, again, under similar driving conditions, I managed to achieve 52mpg, but that's not much better than many C-sector cars achieve now, and the Micra only weighed about 750-800kg as opposed to 1200-1400kg for most current C-sector cars, and whose performance even with a relatively light right foot absolutely smokes the Micra.