Red Sox OF Rusney Castillo -- Drops $85k ... To Pimp Out $84k Porsche

Red Sox outfielder Rusney Castillo only came over from Cuba a few months ago, but he's already BALLIN' OUT like an American ... dropping $85,000 to trick out his $84,000 Porsche!!!

Castillo took his 2014 Avorza Porsche 911 Turbo to Alex Vega and the guys at the Auto Firm in Miami with the following marching orders -- MAKE IT AWESOME!

So what do you get for all that money? Vega says he and his crew took the entire car apart piece by piece to paint it "Snow White" ... then added detailing in red and black, Castillo's favorite colors.

Vega gutted the interior as well to put in red and black leather seats. Watch the video though for the highlight ... a custom grill with Castillo's #38 in lights. There's even a #38 light that shines on the road when he opens the doors.

Castillo signed with the Sox last year for $72.5 million ... so he's not struggling to make payments.