"-I'm definitely replacing Grievious' voice, just don't know with what yet"

How about Mark from 'The Room'?

Examples...

Sith Sidious: The end of the war is near.
General Grievous: You think girls like to cheat like guys do?

Anakin Skywalker: General Grievous... you're shorter than I expected.
General Grievous: As far as I'm concerned, you can drop off the earth.

That's a promise.

Obi-Wan Kenobi: We have a job to do, Anakin. Try not to upset him.

General Grievous: You're the cause of all of this. I don't love you. Get out of my life, you bitch!

Obi-Wan Kenobi: Hello there!
General Grievous: Oh, hey Johnny, what's up?

General Grievous: You don't understand anything, man. Leave your *stupid* comments in your pocket!
Obi-Wan Kenobi: Oh, I don't think so.