I would like to warn everybody: do not buy this very expensive add-on because, you buy it but it will never belong to you.If, like me and a lot of people, you often have to make a clean instalation of FSX after it crash, you must to know that Warbirdsim don't want re-activate your purchase.they are scammers and are very arrogant.They say you have to pay for piracy of others, this is realy amazing!I have a lot of add-on and some have to be activated on-line, but that never been a problem.And sincerely, i think P-51 is just an average add-on and P-47 A2A really is by far better in every way and less expensive.You have been warned...