Floyd Mayweather -- Billionaire Battle Over $3.8 Mil Ferrari

Three different BILLIONAIRES have thrown their hats in the ring to buy Floyd Mayweather's $3.8 MILLION Ferrari ... so says Floyd's car guy ... but the buyers have all asked for special favors to "sweeten the deal."

We broke the story ... Floyd put his ultra-rare Ferrari Enzo up for sale last week -- and now, his personal car dealer at Fusion Luxury Motors, Obi Okeke, tells us the response has been INSANE!

"People have been calling from all over the world ... countries like Australia, Japan, Great Britain, Germany, Austria, India, South Africa, Nigeria and the United States."

But the best part of the story ... Okeke says several people have made full-price offers -- but they each come with interesting caveats.

"I got some crazy request from a 60-year-old man who wants to buy the car -- but only if he can lace up some gloves and spar in the ring with Floyd in his gym."

Here's a list of some of the other requests coming from people who made a full-price offer:

-- Buyer wants a 1-on-1 dinner with Floyd
-- Buyer wants a video shoot with Floyd and the car
-- Buyer wants Floyd to make himself available to take a picture with buyer's entire family

Okeke says 3 of the potential buyers are people who have made Forbes' Billionaires List ... though he says he's going to keep the names private for now.