'Street Outlaws' -- Car Shop Shot Up

The stars of "Street Outlaws" are dealing with a real criminal situation ... after their store was left riddled with bullets.

Oklahoma City PD tells TMZ they are still on scene investigating a shooting at Midwest Street Cars -- where "8 or 9" bullet holes were left in the building.

We're told the shooting happened Monday night -- and since nobody was working -- there were no injuries.

Sources with the Discovery show tell us armed men also showed up at the home of one of the stars -- Murder Nova -- but were scared off when he went outside. We're told there is security footage.

Cops say they don't have suspects or a motive yet.

Story developing ...