Across the United States, auto dealerships are busily replenishing spent or heavily discounted lot stock. Shiny new models are arriving or in transit to rejuvenate sales. Although the volumes are much smaller, ultra-luxury and supercar dealers are doing the same, swapping out the old hotness for the newer, hotter hotness.

This year's broad field of wonder wheels includes notable upstarts from well-established automakers Porsche and Audi. While the names of those companies are easily associated with high-performance, no-compromise vehicles, both have seen fit to up the ante.

Audi announced that it had given its Le Mans quattro concept a green light for production as a 2007 model. That car, dubbed the R8, is to inherit lessons learned from the company's racing group as well as performance division Lamborghini. Although exact production details remain unclear, Audi's investment of nearly $36 million should create a powerful two-seater to be slotted above the incredibly successful TT roadster. Audi's R8 is also gunning for Porsche.

But, the Germans are hardly sitting still. Porsche is offering a $106,000 GT3 version of the evergreen 911. It's essentially a street-legal racemobile. Initial test drives read like detailed travelogues, each minor twist and turn joyfully dissected and analyzed. That's no doubt the natural effect of the 3.6-liter, rear-mounted flat-6 that pumps out 415 horses.

Gleaming Stallion

At higher price points, the Italian stalwarts are also presenting striking models. The Lamborghini Murciélago LP640, which is reported to sticker around $315,000, is a shock-and-awe offense on the senses. Wrapped in spaceship looks, the LP640 boasts a 6.5-liter V-12 that roars to the tune of 631 horses.

Ferrari, meanwhile, is attempting to win hearts and minds with the beautifully designed 599 GTB Fiorano. Although this prancing stallion also has a 6-liter V-12 that develops a slightly more modest 612 horses, its truly stunning frontward lines distinguish it. Its grill smiles more candidly than any Ferrari in recent memory.

Two more exclusive supercar companies, under albeit more pedestrian ownership, are also showing new products. At first glance, Ford's (F) ownership of Aston Martin and Volkswagen's control of Bentley seem to make as little sense as Proctor & Gamble (PG) owning French fashion house Rochas.

But Aston's upgraded and unlimited DB9 Volante and Bentley's Continental GTC prove that work proceeds unimpeded. Both convertibles approach the $200,000 price point. (Bentley's future seems more secure as Aston looks to be up for grabs given Ford's worsening troubles.)

Luxe Lookers

Of course, at prices points higher than $100,000, manufacturers offer luxuries beyond sheer speed. The old world and the old guard are represented by little-known but high-cachet brands like Maserati and Morgan. While the former is banking largely on a large sedan and the latter hopes to make inroads with a speedy little roadster, both offer distinctive vehicles around $100,000, aimed at expanding their brand presence in ultra-luxury niches.

At the topmost end and for the richer-than-God set, Bentley and Rolls-Royce are happy to oblige. Both companies offer models well north of $300,000. Although both the Bentley Azure and Rolls-Royce Phantom feature robust engines underhood to carry the weight of six-figure luxe, each rides best at a slower pace that allows passersby on the street to gawk and stare. What's more, Rolls is reportedly going to offer a $400,000-plus convertible in the near future.

The downside? Many of these 2007s -- by virtue of being custom tailored and highly desired -- have long waiting periods. Even if you're ready to buy now, that may mean your 2007 doesn't show up until 2008.

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