Ars Technica reports that Elon Musk today wrote that Tesla will remove mileage limits on its warranty policy for all Tesla Model S drive units. The warranty, which will still span eight years, won't have a cap on the number of owners for each vehicle. People who purchased Teslas before today were told that the warranty period for the drive unit expired after eight years or once the car logged over 125,000 miles. The revised warranty applies to new vehicles and Model S cars that are already on the road. The article mentions that quite a few Tesla owners have had to have their drive units replaced; out of warranty, that runs about $15,000. Musk's announcement acknowledges that the change may cost the company some money, but says he's "confident it will work out well in the long run."