Good Alternatives to Stock Parts

[radare]

As our XJ's near the 25 year mark, stock parts are becoming less readily available from Yamaha and on the used-market, tend to be worn or worn-out.

In this thread, I'd like to discuss alternatives to the stock parts, which are readily available and make a reliable, bolt-on alternative to the stock part they are replacing.

Three come to mind:

• Polaris fuel pump to replace the stock pump
  VStar650 or FZ6R rear shock to replace the stock rear shock
  McMaster-Carr O-rings to replace stock o-rings for the carburetor main jets, pilot screws and float valve body
  McMaster-Carr o-ring cord stock to replace the stock airbox seal

What else can you all think of that should be on this list? When making recommendations, keep in mind the following: Part should fit and work like the original, without modification. Part should be readily available.