+1 on Tom's thoughts. My entire family works in some portion of the auto industry (service writing, mechanic, auto parts store, etc.) and they all agree that aftermarket warranties are worthless. My Dad is a service writer at a shop and it's his job to contact these aftermarket warranty outfits to request payment prior to charging the customer. He echoes exactly what's been said here so far: that if you don't save every receipt, or don't perform the maintenance at exactly the schedule they want, or in some cases don't use the required performance additives (fuel injectors and other additives), they'll deny your claim.

IMHO, they're a total scam. You pay thousands of dollars for a warranty whose company is absolutely committed to doing everything it can to deny your payment, including fighting you tooth and nail in an arbitration. Not worth it.