Through a combination of mods and tuning, I built a Bruckell LeGran police car with a supercharged 4.3L diesel V6. The engine is a mod called LeGran 4.3 Diesel by STEVIE_G4M1NG, available at https://www.beamng.com/resources/legran-4-3-diesel.20341/. It's based on the real-life 4.3L diesel V6 found in mid-80s GM A-body cars. Not to be confused with the infamous 5.7L diesel V8, the V6 was a better design with fewer reliability issues. I've never owned one, but I've heard cars with that engine could return up to 40 MPG. Some real-life police departments did buy A-body cars for parking enforcement officers, process servers, and other special officers that didn't need the size or performance of a larger car. There's no record of any police department ever using a diesel A-body, but I theorize it would have been a good choice for the aforementioned uses. There was also never a forced-induction (turbocharger or supercharger) option on the real-life engines, but fortunately, a supercharger is an option in the BeamNG parts menu. It's still not quite fast enough to be a pursuit car, but an officer driving one could have theoretically kept up with an offender until officers in faster cars could catch up and take over. My less-than-stellar driving is largely due to my controller's worn-out steering stick. I had to set a relatively large deadzone to keep the steering straight. If you've ever played with a worn-out controller, you know. I know they're not very expensive, but I cannot afford a new one at this time.