While it's not the only car to be powered by Audi's hand-built 2.5-litre TFSI engine, the TT RS remains the lighter, slipperier option - and therefore the sportier one, too. By virtue of its straight-line performance, terrific all-wheel drive traction and dinky footprint, it has earned itself a supercar-slaying reputation. Overtime its design has homogenised with the R8, too - a trait which has arguably been extended by this, the newly facelifted model.
Much like the changes visited on the RS3, the model's minor aesthetic tweaks have been instituted to make the introduction of a new WLTP-conforming particulate filter seem like a mid-life update rather than an inconvenience, but the RS does also gain a new trim level - the Sport Edition tested - and its standard kit list has lengthened.
Certainly the styling alterations are discreet. There are wider grilles in the front bumper and new a LED structure in the headlights, while at the back, the rear wing now features side winglets - which are said to enhance aero performance - and the OLED taillights have gained a new internal design. As standard, the door mirrors are now electrically folding and the windows are tinted, two options said to have been popular with Brits.
Inside, the cabin retains an unchanged Virtual Cockpit layout with the 12.3-inch digital instrument cluster the sole source of infotainment, leaving the dash with a clutter free layout thanks to those ingeniously-packaged climate control knobs. Time has not dramatically aged this generation of TT - it remains fresh and ultra modern in appearance and built without apparent compromise. The now standard inclusion of wireless smartphone charging merely extends its advantage over most rivals.
Press the start button on the steering wheel the Sport Edition's RS exhaust - yep, it gets that too, alongside the 20-inch alloys and that black exterior trim - and the inline five settles into the kind of purposeful tick over that distances it from the comparably rough-sounding Porsche Cayman. Audi Sport has retained identical power and torque curves for the 2019 car, which bucks an industry trend for tapering output or, as seen on the RS3, a shrunken peak torque window. It means that under steady pace the TT's five-pot feels no less eager or excitable, especially once the needle pushes over the 1,700rpm start point for maximum twist. Take it beyond 3,000rpm and the motor feels so elastic that the 1,450kg TTRS's claimed 3.7 second 0-62mph time feels like a worst-case scenario.
WLTP or not, this is a compact coupe still capable of clinging onto the bumper of cars worth twice its price. The Quattro-branded Haldex all-wheel drive system offers immense off-the-line traction - an attribute that hardly seems to slacken when you start applying steering lock. The seven-speed S tronic 'box is quick to upshift and though a tad hesitant on consecutive downshifts, it is more than capable of keeping the motor in its wide sweet spot. From 5,000rpm to the 7,000rpm redline it's all savage acceleration, which only seems to be tamed by the presence of a hard limiter immediately afterwards. The thought of extending the high-end warble with a remap is a hard one to put away...
Perhaps it's the car's lower centre of gravity compared to the similarly rapid RS3 that makes steering it along the winding Old Military Road of Cairngorms National Park the more enjoyable experience. The car hunkers down on its optional adaptive damping, while the steering is weighted well enough to make the front-end's quickness your main source of entertainment. The all-wheel drive system, with its back-axle located clutch, can send 100 per cent of torque rearwards, but don't expect that to add up to much in the real world. No amount of coaxing on dry tarmac will have the RS letting its hair down.
In some ways that's a good thing, because it means the full, lubricious loveliness of the 2.5-litre unit can be unfurled without hesitation. Lean on the chassis sufficiently hard and its proclivity for understeer will key you into its limits well ahead of any disaster - which is the eternal point of Audi Sport's approach to things. The flip side is no less abiding, of course; compared to the Cayman or an Alpine A110, the fun factor is entirely made of one-dimension. Only the single-powered axle of the R8 RWS has endeavoured to buck that trend in recent times; the new TT RS certainly doesn't.
As with the RS3, this fact is unlikely to leave a dent in the sales volume. The TT sells to much the same audience, and for anyone seeking an upmarket and extremely accessible way of going very quickly from A to B, it asks much less of a driver than its rivals would at the same speed. And - to play devil's advocate for a moment longer - the RS's 'baby supercar' label is well-deserved if you grade it on looks, interior ambience, noise and speed. The problem only comes when you apply an additional criteria based on at-the-limit handling. If you can resist doing that, and can afford the Sport Edition, you'll likely be happy with the most expensive - and best - TT that Audi makes.
SPECIFICATIONS - AUDI TT RS (SPORT EDITION)
Engine: 2,480cc, 5-cylinder turbocharged
Transmission: 7-speed dual-clutch automatic, Quattro all-wheel drive
Power (hp): 400@5,850 - 7,000rpm
Torque (lb ft): 354@1,700-5,850rpm
Top speed: 155mph (or 174mph with optional derestriction)
Price: £53,905 (57,905)