AUDI TT

There is only one Audi TT RS in the entire United States right now. And here we are, hurling the black coupe down the front straight at Willow Springs Raceway at 132 mph. We've been invited out to the sunny California desert on a pristine day to flog the hottest-ever Audi TT back-to-back against its TTS sibling, along with a few stints in the all-new S4 and R8 V10 for good measure.

The TT RS isn't simply another upgraded model in the automaker's diversified lineup. The TTS (and the other standard performance models) come from the Audi AG Sport division, while the TT RS was incubated and hatched by Quattro GmbH � the team who brought us the nefarious R8, RS4 and RS6. And while we've seen the TT on our shores with four- and six-cylinder powerplants, the new five-cylinder engine marks a significant departure for the front-engine coupe and convertible (even as it pays homage to the original 1980s-era Audi Sport Quattro).

So what makes the TT RS special and how does it fit into the current TT lineup? More importantly, how does the enthusiast-tuned package work under demanding track conditions? We intend to find out while answering a very important question for Audi: Should it bring the TT RS to the States?

Pop the front hood of the TT RS and you will observe a beautifully finished transverse-mounted inline-five complete with painted red valve covers. Displacing 2.5-liters, the iron block/aluminum head powerplant features direct-injection and turbocharging to squeeze out a robust 340 horsepower. That's admirable power, but more impressive is the 332 pound-feet of torque starting at just 1,600 rpm (the TTS makes 265 horsepower and 258 pound-feet of torque from its 2.0-liter turbocharged four). Mated to a new six-speed close-ratio manual transmission � the only gearbox offered on the TT RS � power is predictably sent to all four wheels through Audi's Quattro system (using a specially-modified Haldex multi-plate clutch). The automaker says the TT RS will sprint to 62 mph in 4.6 seconds (cutting half-a-second from the TTS). Top speed is limited to 155 mph unless you opt (pay) to have it removed for the enjoyment of explaining to the judge why you were doing an unrestricted 174 mph on Interstate 95.

In addition to the unique engine and transmission, the suspension is also upgraded (lowered ride height and firmer springs). However, Audi's magnetic ride adaptive damping system wouldn't be offered in the U.S. market if Audi pulls the trigger. The brakes are upgraded to 14.57-inch rotors with four-piston calipers in the front (the TTS wears 13.4-inch units) while the rears share the TTS' 12.2-inch diameter discs with single-piston calipers. Our test model was sporting 255/30R20 Continental tires on all four corners.

The TT RS is physically differentiated by its unique front fascia (including a jet black RS-line honeycomb grille), side skirts and special rear diffuser with dual oval exhaust tips (the sport exhaust option receives black tips, not chrome). The pop-up spoiler is gone and replaced by a fixed rear wing. Additionally, if the model makes it to our shores, it will arrive with brushed aluminum mirrors and exclusive 20-inch wheels (our TT RS had carbon-fiber mirrors and Euro-spec 20-inchers). The interior has a delectable dimpled-leather, flat-bottom steering wheel with a thickness that seems to match the diameter of a Red Bull can (we exaggerate, but it's close). Other cosmetic touches are found on the instrument panel and console. Sadly, we can ignore the sport seats in the pictures � they don't meet our DOT standards.

Overall, the RS package really adds an aggressive edge to the TT's modern styling � it has sex appeal, but the black exterior doesn't show it best. From the front, side or rear, the special aerodynamic package makes the TT look expensive. It reeks of exclusivity (Audi verbally reinforces that point as it mentions an expected low sales volume if it arrives). You won't see yourself mirrored in a TT RS at a stoplight. Trust us.

We spent several hours lapping Willow's "big track" in Audi's hottest cars. As expected, the R8 V10 is pure mechanical bliss � few things in life are more enjoyable than viewing a wide open track through a closed helmet shield from the R8's driver seat at 140 mph. Even the family-oriented S4 sedan never ceases to amaze us with its civility, balance and track prowess. But we need to focus on our stated objective: To wring the tires off the TT RS.

The TTS and TT RS are both very stable and confidence-inspiring on the track, but the RS model is much more at home thanks to its special powertrain. We particularly enjoyed its six-speed manual transmission � reinforcing our complaints about Audi dropping the option from the TT in 2010. The gearbox seemed very suited for its intimate relationship with the turbocharged five. Willow Springs is a big fast track that has most cars running in third or fourth gear to hold their normally-aspirated engines in the power band. Thanks to the aforementioned low-end torque, the TT RS preferred to pull strongly solely in fourth and fifth gear � there wasn't a need to drop into third unless you were looking for a few remaining tenths in a fight for the podium.

With its 403-pound engine transversally-mounted in the nose (along with its weight bias), the Audi TT RS eventually understeers when driven at its limit of adhesion (you'd be hard-pressed to notice it outside racing conditions in the RS). Unlike other TT derivatives, the RS' turbocharged five-cylinder's massive torque reserves allow bold drivers to give the coupe even more gas in these situations. With some weight immediately transferred to the rear wheels and a bit more steering input, the all-wheel-drive TT RS seemingly cheats the laws of physics as it howls around the corner holding its line.

Our sole grievance � just one � was only evident at triple-digit speeds. When the brakes were firmly applied at 125-plus mph the TT RS would get light in the rear end and nervously oscillate until speeds dropped down to about 80 mph. Since this didn't occur with the TTS, we figured it was the either the overheated street tires, suspension settings or a poor alignment on this particular tester.

Bust out the spreadsheet and you've got a good idea of where the TT RS fits in. Included in the range are the TT, TT "S line," TTS and the not-yet-available-here TT RS. The standard TT coupe starts at about $38,000 (add $3,000 for the drop-top). Opting for the "S line" sport cosmetic package adds another $2,200 to the price. The TTS variant is delivered with an upgraded engine and other performance modifications with a starting base price of $45,900. Audi won't give us estimated base pricing for a U.S. model TT RS, but they did assure us it would cleanly undercut its targeted Mercedes-Benz SLK55 AMG (base $66,650) and Porsche Cayman S (base $61,500). With an estimated 0-60 time of 4.4 seconds, it should run at the front of the pack too.

This track exercise was designed to tease a handful of American journalists with the next-best-thing to the R8 flagship in Audi's arsenal. It worked. The TT RS is a big step up from the TTS. Not only do you get the terrific lag-free turbocharged five and the slick six-speed manual transmission, but it comes with the looks and performance to justify its (um... theoretical) segment-beating price. The Audi team here in the U.S. really wants to bring it over as a halo car (not for its sales volume or potential profit), but the folks back in Ingolstadt need some encouragement. The logic says if Autoblog liked the TT RS, our readers would be the first to hear about it. With that mission in mind, and a set of worn and corded 20-inch tires left back at the track, we say go for it Audi.