WE are about to witness one of the most significant automotive environmental revolutions, as sulphur-free petrol is gradually introduced to forecourts nation-wide.
It will be available within a few weeks, and by the end of next year should be on offer at every filling station in the country.
Sulphur-free petrol is a development of Ultra Low Sulphur petrol, which has been around for more than a year.
This latest development reduces the amount of sulphur from 50 parts per million in ULS petrol to just 10 parts per million, which is reckoned to be low enough to earn the tag Sulphur Free.
Sulphur combines with moisture to form sulphuric acid, which is strong enough to erode stone buildings, so you can imagine what it does to your lungs.
The introduction of sulphur fee petrol follows the advent of lead free petrol, which is an extremely significant environmental boost.
Among the vehicles most suited to the use of the new fuels are Audi's new FSI direct injection models, which boast enviable levels of fuel-burning efficiency.
They can operate on sulphur-free fuels with absolutely no loss of performance, whilst boasting just about the lowest carbon dioxide emissions in the process. This is because the same efficiency that enables them to run happily on less rich fuels means that they also burn more of the harmful particulates of carbon.
The benefits to the driver are low tax liabilities for company car users, and hopefully cheaper petrol for private punters.
At £19,565 for the two-litre A4 saloon, and £20,695 for the Avant estate model, they're not exactly cheap, but they are an exceptionally sound investment.
Such is the reputation for outstanding quality, reliability and durability of the A4 that its residual values are about the best in the business.
No sooner did the new A4 go on sale than it was universally declared the best junior executive model on the market, ahead of even the BMW 3 Series and Mercedes C-class. It has taken top honours in every newspaper, magazine and television poll, and surely they can not all be wrong.
Looks are obviously subjective, but what makes the roomier new Audi so special are its attention to detail and the superior way in which it responds to the driver's instructions.
By being such a class act, it has raised the standards to a point where its rivals are now being forced to rethink their strategies in order to attempt to regain the lead they have held for so long.
Such are Audi's hopes for the latest A4 that the company is predicting a minimum of 25,000 buyers a year. With prices ranging from £17,690 to £25,005, they are less expensive than their rivals, and have the best residuals of all.
Although the latest incarnation may look little changed from the outside, there are major structural refinements, and new engines. The high-tech 2.0-litre four cylinder and 3.0-litre V6 petrol units make the A4 a serious rival for similarly endowed versions of the BMW and Merc models.
Despite draconian taxes for large-engined cars, it is a format that continues to appeal to a significant number of company user-choosers who value performance. In the case of the 220bhp V6, there are is a 0-60mph acceleration time of 8.5 seconds, and a top speed in excess of 145mph. The 180bhp 2.5-litre V6 diesel unit uses sheer size in preference to a turbocharger to achieve its performance, which enables it to rival BMW's acclaimed 330d.
The A4 epitomises Audis' eternal quest for engineering excellence, with greater use of weight-saving plastic, magnesium and aluminium for many body panels and components. Unlike the small A2 and the large A8 models, however, the body of the A4 remains primarily steel rather than all-aluminium. Despite being 70mm longer 33mm wider and 13mm taller than the previous model, it is 45 per cent stiffer, yet weighs no more.
A very comprehensive line-up of extremely sophisticated cars, the choice now includes petrol engines of 1.6, 1.8, 2.0, 2.4 and 3.0-litres, plus 1.9 and 2.5-litre diesels with various power outputs.
Pick of the bunch is the two-litre FSI, which offers by far the best compromise between performance and economy, with the bonus being commendably low emissions.