None of the custom upgrades will increase the performance of a bike. Items like Gold Frame, black tires, decals, etc are just for looks and provide no performance benefit. The only way to go faster is to the have the fastest bike and to play like a pro! We recommend playing against some of the top guys in the game to s...
When you beat a Pro boss you will unlock "all upgrades" on a bike. This means that the bike can now be upgraded to the max amount of 28 in all attributes (speed, pump and jump). This is the same as bike 7. This means you can race on bike 1 (or any Pro bike), but at the same speed, pump and jump attributes as bike 7...