Most mods start because a modeler guy wants to model certain car. Maybe he knows about what sims have better physics, maybe not. Maybe he cares if the physics will be very accurate, maybe not. That is the very first thing that you seem to ignore. Second thing, complex engines are nice when you can have full knowledge of how they work; if not then you are in trouble. Practical example: who knows here how all the aerodynamic values work in the rF2 physics engine? If anyone knows, why don't share it with the community? Well, this second thing probably answers the first one. And no, I don't want to hear "this value increases the downforce loss with height", I want the exact equation. Because we are talking about hardcore perfect-to-death-accurate-physics, right? Third thing, there is the "lack of data" that all physics guys have to face. You say that rF2 physics are realistic. Ok. Now my question is, how do you know (I mean, based on facts)? Do you have tire data from the manufacturer to know if the virtual one behaves exactly like the real one, for example? And second question from a modder view; if you don't have such data to compare; why does it matter how complex the engine is, if you don't really know if the outcome is accurate or not? So in conclusion, knowing how many incognites do we have, a better/more complex engine not always means that the outcome is more realistic. In fact, it gives more opportunities to mess up something. And, of course, if we are positive, it probably gives more opportunities to make something better than with other engines. So before talking about "performance and handling", first think about such things.