I have nothing to do with the new Telegraph buying guide. JD Power relies on car owners filling in questionnaires and to my mind that is a very poor way to research anything. If you ask people questions you do not get honest answers. You only get honest answers if you trick them. However, Warranty Direct's data is based on actual warranty claims: their frequency and their average cost, for cars which, of course, are out of the manufacturers warranty period, otherwise the owners would not be WD policyholders. So for cars more than 3 years old I'd trust WD every time. And if you want specific descriptions of what goes wrong with all makes and models, go to www.honestjohn.co.uk/carbycar and look in the 'good and bad' sections. Most of that information has come directly from owners who have emailed me with it.