It would be interesting if dry sump oil systems could be equipped on high-performance engines. of course, things like increased oil volume, oil cooling, and modified weight distribution can already be done, but preventing oil starvation when the engine is upside down, which is the main change, would be quite a handy feature in high-end rock crawlers and rally cars. I presume G-force induced oil slosh isn't a thing yet, but a basic system to simulate it would make it useful even in on-road race cars, and another difficulty in trying to cheaply upgrade a car, which is always fun.
I'm pretty sure piston-driven aerobatics planes use a system capable of running upside down, but it might be a specialty system not used on cars. still, the oil slosh would be an interesting effect which not many other games simulate.
