Justin Bieber's Ferrari -- PULLED OVER for Speeding ... Seriously

Unbelievable -- Justin Bieber's white Ferrari has just been pulled over for speeding ... just days after Bieber allegedly tore through his gated community in the same car, terrorizing his neighbors.

Bieber wasn't behind the wheel this time -- the culprit was his good bud Lil Twist ... the same bozo who was driving Bieber's white Ferrari when that photographer was killed earlier this year.

Law enforcement sources tell TMZ ... police pulled Twist over as he roared out of Bieber's gated community in Calabasas ... but they let him off with just a warning. To that we say, HUH?