In what? Engine? Gearbox? diff (it it has one)?
How often do you plan on changing it?
What engine is it?
how do you drive it?
What's the maximum temp it will see?
If turbo'd, what type of turbo, bush or bearing?
If turbo'd, what boost do you run?
How about giving us some more to work with and save us the trouble of trying to work out what you are on about.