My partner's old hyundai genesis always "smelled" like the engine had been running "hot" despite being fully OEM with no mods. Any time she drove back from a store and parked in the garage, I could go out an 20 later and smell that hot metal engine. Never had another car that smelled like the engine was running hot/hard.
Car only lasted ten years before the timing chain slipped off the pulley and destroyed the engine block. We'll never own another hyundai/kia product ever again that's for sure