Listened to “Fist Bump” again.
And I think it probably won't be better with Crush 40.
I know, lots of Crush 40's songs are great. I love “Live and learn”, “What I'm made of”, “Knight of the wind” and so on, but not everything is better with Crush 40. One example, “Free”, the theme song of Sonic Free Riders. Although the game's motion controls are crappy, its main song (non-Crush40 ver.) is one of my favourite songs from Sonic series. But its Crush 40 version feels strange to me. I think the song's style doesn't really fit the style of Crush 40, so it will definitely come out not as good.
Will Fist Bump be better if Crush 40 sang it? Who knows!