I've been playing the superb Out Run by Jotego since it was released. When you look on Twin Galaxies they have the arcade world record at 52,897,690. Default settings, which means normal cars and normal time. I think the speed boost at the beginning is allowed, but I don't think the Gear Gacha cheat is, I'd be amazed if it is.
So after playing for a while I think the only way to get this kind of score is to have a totally clean drive and never brake once.
I have managed 47,000,000+ by following what is supposed to be the fastest path:
Stage 1 - Coconut Beach - can be done with no braking
Stage 2 - Devil's Canyon - can be done with no braking
Stage 3 - Alps - Brake on second bend, slight brake dab at the end
Stage 4 - Wheat Field - can be done with no braking
Stage 5 - Autobahn - slight brake in middle
I can't see how to make up the extra 5 million points. Maybe lifting off the accelerator early before the corner instead of braking? I also think there is a way to complete the final stage Autobahn without braking. It involves hitting the bends and crossing over the central reservation between the small gaps in the bushes, but you need a lot of luck with the car positions and great timing in the gaps.
Anyone got any other ideas?