Maybe dp3 odometer can save my business

I owe one BMW750 08.I love it .but recently ,some unlucky thing happened ,my business went down. I need a large sum of money urgently. What’s the worse ,the bank refused to loan to me .So I ask my friends and family for help .They are all kind to me and lend me a considerable number. But it still lack some money. The only way I can think of is selling my love 750.It’s a hard decision .750 be a partner with me for 4 years already, but in order to get my business back I have to . 

Several days ago , I drove my750 to the second-hand car market ,the vendor quote me a low price which make me very surprise. The vendor told me my 750 have drove for a long mileage so it couldn’t sell a good price . That’s very disappoint me ,my 750 is more than the value in my mind. ‘’Mark,what are you doing here?’’ That’s from my old friend Davie . I could just see his happy from his face.I told him what I’m going to do.Davie sold his car just now .He whispered to me that he used the digiprog 3 to reset his odometer so that it can sell a good price .And he persuade me to do that owing to my situation. Should I use this dp3 odometer?Is it legal? By the way ,my car is still great.