Porsche unveiled a 718 horsepower topless hybrid supercar concept at the Geneva Motor Show to an extremely receptive crowd, becoming the most surprising and most talked about car of the show. Porsche now says it is looking for letters of intent from possible buyers to determine if the car has production potential.

Toyota officially recalled its 2004-09 Prius hybrid models last November for floor mat issues – including both models involved in the latest cases of unintended acceleration – but the Japanese automaker is reportedly still working on a complete fix to the floor mat problem.

Nissan’s Infiniti luxury division is turning 20, with the Japanese automaker announcing four limited edition G models to mark the momentous occasion. Dubbed the G Anniversary Editions, the special package will be available on the G37 Sedan, G37 Sedan AWD, G37 Coupe and G37 Convertible.

Ralliart, an independent tuning firm that has long been associated with both aftermarket and factory-endorsed Mitsubishi products, announced this morning that it will cease operations at the end of March.

Just one day after an out of control Toyota Prius made news headlines in California, another episode of unintended acceleration in a Prius vehicle has taken place in New York. The latest victim wasn’t so lucky, though, slamming her out of control 2005 Prius into a stone wall.

For the first time ever, GMC will offer a luxury-laden Denali variant of its hauler-friendly Sierra HD pickup range. The truck unit of General Motors will now offer a Denali version on all but one of its mainstream consumer offerings.

Cadillac has begun enacting major policy changes in an effort to distance the luxury brand from its parent company, General Motors. Cadillac has been owned by GM since 1909, but now wants to establish itself as a unique luxury brand away from the negative publicity associated with GM’s bailout funding.

The United States’ “cash for clunkers” program was rather controversial when it was first enacted last year, but a new study by Maritz Automotive Research Group indicates the CARS program was highly effective at generating new car sales.

Ford has announced zero percent financing for as long as 60 months on select 2010 models, following similar moves by Toyota and GM. Ford will offer zero percent for 60 months on Focus and Fusion, and 72 months for the soon-to-be-replaced Explorer and SportTrac, as well as the aging Ranger.

Following in Toyota’s footsteps, Mazda has announced it will install a brake override system on its future models. Toyota announced it would launch a brake override system on its 2011 models following two safety recalls involving nearly 9 million vehicles worldwide.

Volkswagen’s premium Audi division has been on a sales roll as of late, and looks to continue that momentum as the first quarter nears its end. Following two strong months of sales, Audi is calling for much improved first quarter results.

Congress has not requested that Toyota produce the memo that was sent to it by a band of six concerned Toyota workers attempted to warn the automaker of impending quality and safety concerns back in 2006. The report says that Toyota never acknowledged the memo in 2006, but Congressman Edolphus Towns of the House Oversight and Government Reform Committee is requesting Toyota produce it by March 10.

General Motors officially announced the wind down of its Hummer brand following the failed sale to China’s Tengzhong last month, but the iconic off-road brand will apparently get one last go as the Shreveport factory’s H3 line will reopen for one last production run.

Ford Motor Company announced today that communications giant AT&T will be its first customer for the Transit Connect Electric commercial van. The announcement from Ford comes despite AT&T’s increasingly close relations with General Motors, whose chairman and CEO formerly led AT&T.

If you name your star vehicle, and perhaps your biggest profit maker, a Super Duty truck, you’d better be able to “bring it” when the chips are down. With a renewed vigor in the Dodge Ram stables, and continued pressure in the Chevrolet and GMC camps, it hasn’t exactly been a cakewalk for the venerable Dearborn, Michigan, concern.

Mercedes-Benz’ AMG division has officially taken the wraps off its new 5.5L biturbo V8. Essentially marking the end of large displacement engines at the Mercedes tuning shop, the new 5.5L will bow later this year and will eventually spread throughout most of AMG’s lineup.

Mitsubishi has announced it will supply French car maker PSA/Peugeot-Citroen with 100,000 units of its i-MiEV electric vehicle. The i-MiEV will be sold under PSA’s Peugeot and Citroen brands, at a combined rate of about 25,000 units per year.

The California Highway Patrol has confirmed its officers helped bring to a stop a runaway Toyota Prius exhibiting unintended acceleration Monday afternoon. The incident took place around 2:00 p.m., a CHP spokesman told Leftlane.

Germany’s Daimler has been forging new partnerships over the last few months – including tie-ups with Tesla Motors and China’s BYD – but the German automaker will reportedly reduce workload by shedding its stake in India’s Tata Motors.

Following a confirmation late last year, Acura has announced it will unveil its TSX Sport Wagon later this month at the New York International Auto Show. The 2011 TSX Sport Wagon is set to take to the New York show stage on March 31.