When it drops, it drops to around half that value. The exception is on the Monaco course, where a few turns cause the frame rate to drop to the single digits. You can contrast these titles to Tokyo Xtreme Racer which suffers from both slowdown and frame rate loss. The two early titles look great. Cars have a natural look to them, and the trackside detail is spectacular.
Trees have a particularly pleasant look, even at close range.
Sega Rally 2 also exhibits extra animations in the backgrounds. But what both titles do have is some aliasing. If you look closely you will see some aliasing. Not much, mind you, but it is there. Moving to Sega GT, I basically found the same graphical quality as Sega Rally 2 but with no frame loss and less draw-in.