Depends on how you define "best". For hard driving my vote would go to Redline and Fuchs. M1/Amsoil/Castrol/Havoline etc. are all great too but under extreme conditions I'd say the first two above are more ideal.
I though running 5w-20 was pretty radical and you have a good question, because it looks like a 5w-20 in a new engine had better be a good oil. There is little margin for error. But, I just met someone that went one step farther. He has a new Acura TSX and 5w-20 wasn't good enough. He's running Maxium4 Ultra (hope I have the name right right) 0w-10. His car is a tuner car with suspension mods, aero kit and a hopped up engine, beefed up clutch and a loud exhaust. He says he drives it hard and has 11k miles, since he dropped the money on the mods and it runs great with the 0w-10 oil. He let me drive it and told me to hit it hard, which I did. I really like this car. It's really fun to drive, something I can't say for a lot of cars I've driven. Maybe there is something to these thinner oils, like better performance.