McLaren released film on Tuesday of two versions of the new testers, called the XP8 and the XP10, which it says are in the "beta phase" of development. They move the project closer to production guise with a new version of the M838T twin-turbo engine, transmission with new gear ratios, an improved cooling package, new suspension geometry and upgraded electrical architecture. The 3.8-liter V8 is expected to make about 600 hp and work in tandem with a seven-speed, dual-clutch gearbox. The weight should come in at less than 3,000 pounds. Look for a sticker of about $230,000 when the car goes on sale in 2011.

In addition to the technological developments, the cars are clad in a black plastic vinyl, in contrast with the black-and-white camouflage of the 2009 prototypes.

Testing is being conducted around the world, and McLaren's video shows the cars on a Spanish proving grounds and hitting public roads.

First revealed last year, the two-seat, mid-engine MP4-12C will be positioned to fight the Lamborghini Gallardo and Ferrari's F430 and 458 Italia.

Channeling a "Formula One intensity" seen in its racing program, McLaren says it has 20 to 25 technicians traveling with the prototypes to speed development. Another 12 engineers are also focusing on specific elements and technologies.

Final performance figures are expected to be announced in March.

"Between now and production, the vehicles and the team are working flat-out," Mark Vinnels, McLaren Automotive program director, said in a statement.