NY Mets' Yoenis Cespedes: TREAT. YO. SELF. ... Gets New 'World Series' Ride

NY Mets superstar Yoenis Cespedes decided to reward himself for getting to the World Series this year -- so he dropped $75k to pimp out a brand new 3-wheeled super car ... TMZ Sports has learned.

Cespedes has become OBSESSED with designing and customizing whips -- especially with Alex Vegas from The Auto Firm in Miami.

So, all he needed was an excuse to splurge on a new ride -- and the World Series run felt like the perfect reason.

The result? A custom Avorza Polaris -- with Avorza red and grey leather seats and a custom red #52 on the hood.

In total, Cespedes put $75k worth of work into the $20k car ... and the end result is pretty sweet.

It'll look pretty good next to that fire-breathing Lambo that's already in his garage ...