This protector set covers the vulnerable plastics in the game. Remove the steel washers that ding up the ball when you install a protector.
There are two parts that you won't need to install until you shop the game. The first is the large plastic that goes under the warp ramp, and requires significant disassembly to replace.
The second is the long, complex piece that goes under left side of the Vengeance. Use the short pice beside it to protect the vulnerable nose - just make sure that it is properly aligned.