Matthias Mueller, currently head of Porsche, is expected to be named the new VW CEO.

Volkswagen AG is expected to appoint Matthias Mueller, the head of its Porsche sports car division, as its new chief executive, replacing Martin Winterkorn, the executive ousted in the wake of a scandal over the rigging of U.S. diesel emissions tests.

The 62-year-old Mueller will be formally named tomorrow during a meeting of VW’s supervisory board, according to the Reuter’s news service. He will have to oversee what has become the biggest crisis in the history of what this year became the world’s largest automaker. Among other things, Mueller will face a company with a number of management vacancies, the scandal expected to trigger a cascade of firings as the VW board seeks to punish those responsible for the emissions test cheating.

Longer-term, VW faces a variety of legal actions as regulators and other authorities dig into the scandal which was touched off by the recall of 482,000 vehicles in the U.S. but may eventually involve up to 11 million diesel-powered products sold worldwide.

With a growing number of class action lawsuits in the work, VW itself has “lawyered up,” hiring well-known defense firm Kirkland & Ellis LLP, the same legal team that handled things for BP after the blowout of its Deepwater Horizon drilling rig in the Gulf of Mexico.

The VW executive committee said Wednesday it is “expecting further personnel consequences in the next days,” going after those responsible for the scandal, touched off by the recall of 482,000 VW diesel vehicles. According to the Environmental Protection Agency, VW used hidden software to get them to pass emissions tests, though they produced up to 40 times the legal limit of emissions in real world use.

(CEO Winterkorn’s fall from grace came surprisingly fast. Click Here for the story.)

Ousted VW CEO Martin Winterkorn.

How extensive the effort to game emission tests will prove to have been is uncertain, though Mike Jackson, CEO of U.S. megadealer AutoNation, said he believes the problem is “systemic,” and not just the results of “a few bad apples.” It would have required a wide range of engineers and others to identify the problem, come up with the idea of a fix, then program the so-called “defeat device.” Others, including those in marketing, may also have been aware of the scam, industry insiders contend.

While now-ousted CEO Winterkorn claims not to have been aware of the cheating plan, many observers have their doubts, noting his reputation as a very hands-on micromanager who previously oversaw the company’s engineering operations.

Among those who could be forced out in the coming days are Audi R&D chief Ulrich Hackenberg, and Porsche’s research director Wolfgang Hatz. Heinz Jakob Neusser, the R&D boss for the VW brand might also be vulnerable, according to various reports from Germany, including one by Germany’s Bild newspaper.

In the U.S., several news services have pointed to Michael Horn, the CEO of Volkswagen of America, as likely to be axed. A 26-year VW veteran, Horn took over that post early last year in a bid to reverse declining sales. Like his predecessor, Horn had put an emphasis on diesels as a way to differentiate Volkswagen from rivals like Toyota, Honda and Chevrolet. During the last several years, those “oil burners” have been making up about a quarter of the company’s U.S. sales.

(This wasn’t the first time VW was caught cheating. Click Herefor a look at its previous problems.)

According to German reports, Horn is likely to be replaced by Winfried Vahland, currently the head of VW’s Czech-based Skoda brand. The maker will, meanwhile, now have a post on its management board specifically representing its American operations.

Asked about Horn, a U.S. spokesman for VW said, “We don’t comment on media speculation.”

VWoA CEO Michael Horn, shown with the CrossCoupe Concept, could also be out.

VW’s revised management team will have plenty of challenges to deal with. Among other things, they will have to find a fix for the 482,000 vehicles recalled in the U.S. But the number could grow bigger and spread beyond American shores. Before his resignation, Winterkorn revealed that the suspect software was programmed into 11 million vehicles sold worldwide, though it was not activated in all of them he said.

German Transport Minister Alexander Dobrindt said Thursday that efforts are underway so see how many vehicles “apparently affected are in Europe,” adding, “That will be cleared up in the next few days.”

(VW scandal a “black eye” for US diesel market. Click Here for the story.)

Authorities in other countries, including South Korea, are also looking into the reach of the scandal. The U.S. EPA is continuing its probe, and VW could conceivably face fines of about $18 billion for violating the Clean Air Act. Meanwhile, the Justice Department reportedly has begun a criminal investigation.

Add to that a growing list of civil litigation. California-based Girard Gibbs LLP is the latest to prepare a class action lawsuit which it has filed in both the U.S. District Court for the Northern District of California and the Central District of California.

By bringing in its own legal team at Kirkland & Ellis, VW clearly doesn’t plan to roll over and hand out cash to anyone who asks, but few expect the maker to try to deny it cheated. And, if anything, AutoNation’s Jackson said he would hope Volkswagen would recognize the need to put consumers first and only then try to figure out what it all will cost. Earlier this week, the German maker set aside $7.3 billion to cover the scandal’s costs.