I remember when i had my old 99 honda civic Gli model. The engine block was showing shaking visually as you would of course. it was nice to see it shake, that's just due to the primitive engine mounting systems at the time. Basically any car 2000's all the way down to 19010 should have engine block shake based on what you're doing to it, i know whilst idileing should shake as well. Some tinkering and research would be need it to get the right ammount of "boogie" in the each block. Obviously more modern cars would not have this as obvious due to modernisation and what not.
This feature already exists, it just might not be as pronounced as your old civic, but it exists and is even amplified through a car's older age/ larger engine displacement/ larger cylinder count
that's awsome! but i can't really see much of that diffrence. maybe it's not obvious or needs more sensitivity?
Engines (even older ones) shake when they are unbalanced, which is in most cases caused by an issue. In beam if you open the hood and rev the car during rpm change you can see the engine tilt which is realistic. It should not shake when idling or at constant rpm, i can only think of dragster engines that shake which are tuned for top end performance and work poorly on low rpm and load. Only small engine vibration that can barely be noticed in game can be normal.