In Saints Row: The Third (aka Saints Row 3) for the PS3, and Xbox 360, there are some vehicles that aren’t supposed to be customized, so is there a way to customize these uncostomizable vehicles? Luckily, there is a glitch in the garage that will let you customize any vehicle in the game.
Take any customizable vehicle into Rim Jobs, and press Y (Triangle on PS3). Go to Garage in the menu, and selct a vehicle that is not customizable from the list, but do not retrieve it. Press B (Circle on PS3) to go back, and then select Accept to exit. This should take you directly to the customization screen for your vehicle that isn’t customizable.