Should I get the gears polished? I have heard that if you don't that the gears will be making a louder that normal noise! But on the other hand I have also heard that polishing is a waist of $. Has anyone had the experience on this subject? Thank you !

The gear noise depends on the cut of the teeth not the polish. If its something you can't see anyway like a cam gear set, dont bother. When you order it ask the manufacturer if they have a "quiet" and "noisy" set, as they usually do. Also if this is a gear drive setup for the camshaft on a fuel injected car DO NOT DO IT. All gear drives generate enough harmonics to make you detonation sensor go apeshit. Your ignition timing will be all over the place, if it will even idle.