I hope this is on your to-do list already, but just in case.
The manual transmission with manual clutch is not very realistic. When you set a gear in BeamNG, you just gain speed, regardless of what you do with the clutch or throttle. In real life, your engine would just stop. In order to get your car moving, you have to slowly release the clutch pedal and usually get more RPM, because very few motors are able to run at the base neutral-gear RPM.
Also, you're not able to turn off the engine...
More realistic manual transmission
The manual transmission with manual clutch is not very realistic. When you set a gear in BeamNG, you just gain speed, regardless of what you do with the clutch or throttle. In real life, your engine would just stop. In order to get your car moving, you have to slowly release the clutch pedal and usually get more RPM, because very few motors are able to run at the base neutral-gear RPM.
Also, you're not able to turn off the engine...
More realistic manual transmission