IT'S 25 years since Audi set the car world alight with the first of its RS high performance models.

That car was an RS 2 Avant powered by a 2.2-litre five cylinder engine developing 315ps - not at all shabby for a vehicle back in 1994.

Today there are six RS derivatives in the Audi stable and the line up has just been updated with new versions of the TT coupe and roadster and RS 3 hatch and saloon coming on stream.

All models now meet the latest emissions regulations and come with petrol particulate filters as well as modest changes inside and out.

Mechanically there is no difference to their immediate predecessors and the new RS models are powered the latest iteration of Audi's now fabled 2.5-litre five cylinder engine, turbo boosted to 400ps.

That produces truly hot performance with 0 to 60 acceleration times of just 4.1 seconds for the RS 3 , 3.7 seconds for the TT Coupe, and a top speed - which for an extra £1,600 - can be unleashed to 174mph.

In the case of the Audi TT RS Coupe we have just tried that, and a few other extras took the price of the car up from a ‘basic' £56,335 to £67,120.

For a 2+2 that is top dollar but the Audi delivers a sumptuous drive that is worth every penny.

Quattro all-wheel-drive, magnetic dampers and an RS exhaust system that creates a wonderful sound with dynamic mode engaged are all part of the package.

So are sporty tweaks such as alcantara covering on the steering wheel, a special finish to the leather upholstery and carbon inlays on the centre console.

On the outside there were black Audi rings front and rear, a spoiler on the boot lip and red brake callipers peering through the alloys.

The treatment for the RS 3, while similar, is not quite as ostentatious yet the cars still look the part with wider tracks and flared wheel arches setting them apart from regular A3 models.

While a little less involving inside with a retractable display screen and no starter button on the steering wheel a la TT both versions of the RS 3 are still beguiling to drive.

And for outright performance cars they are also practical with the booted saloon having 315 litres of space and the Sportback 20 litres more.

However, of the two we just tried there was quite a difference to their feel with the saloon having noticeably softer suspension.

Fuel economy from all three RS models was impressive for such firepower with the TT and RS 3 saloon showing an average of almost 30mpg and the Sportback returning a very creditable 35 to the gallon over similar routes.

Officially the RS 3s are each rated at 29.7mpg with emissions of 194g/km while the TT Coupe comes in at 30.7 with a CO2 figure of 181g/km.

Prices for the RS 3 start from £46,285 for the Sportback and £47,285 for the saloon while Audi is also offering Sport Editions on its new RS models which for an extra £4,000 adds black body details - including the badges - and 20-inch alloys on the TT.

The RS 3s Sport Editions get similar treatment but sit on 19-inch wheels and all share the same exhaust system with its compelling growl.

Compared to alternatives from the likes of BMW, Mercedes and Porsche, Audi has found a niche of its own with its RS cars.

They are exclusively finished for an exclusive audience which demands a car that packs a punch without shouting it from the roof tops - conservative but so compelling.