No, Ferrari badges do not add value to your car.
One of the truly great things about the original Dino 246 GT, built by Ferrari but not technically branded as one, is that the beautiful and graceful lines of the car's Pininfarina body show off everything that was right about Ferrari in the Sixties. It is an unquestionable work of art. Mazda has also built a car which is very near perfection, and while its bodywork isn't nearly as exquisite, every ounce of the MX-5 is in just the right place for perfect balance.
So one enterprising MX-5 owner has decided to ruin that perfect balance of his car while simultaneously attempting to do serious harm and insult to the legacy of the Dino. He has decided to give his car a sort of Dino look, despite the engine being in the wrong place for that, and is now selling it on eBay. The asking price is hilarious in its impossibility, $29,000 for a ruined '93 Miata with 88k miles on it. The owner will tell you that it is only about one tenth the usual going price of a Dino 246 GT, but that really isn't how car values work.