That may cost the consumer years of warranty protection because many car manufacturers limit performance guarantees to drivers who use manufacturer-authorized parts for all repairs.

Some consumer advocates question the contracts' value, pointing out that warranty protections have improved significantly in recent years.

In return, these critics say, consumers get little or no additional warranty protection.

If you've ever bought a new car from a dealer, chances are it came with some kind of warranty protection.

Audi of America Inc., whose sales have been affected by lawsuits over the unintended acceleration of some models, said it would offer buyers increased warranty protection.

Audi subsequently offered increased warranty protection and renamed the affected models - with the 5000 becoming the 100 and 200 in 1989.

If you've ever bought a new car or one with reasonably low mileage from a dealer, chances are good that it came with some kind of warranty protection.

How deeply a buyer should be concerned with warranty protection will depend upon where the house is located.

For the general public, however, the lack of technical support and warranty protection (other than what is provided by the individual component and software manufacturers) may be a significant disadvantage.

As for simple product defects, all three issuers offer extended periods of warranty protection.