Question From a Noobie

Well...like any self respecting teenager, i have questions, for now i shall limit myself to 2.

First: i know the term dark side refers to a hemi, (specifically a big block? or thats all hemi's can come with? Still don't quite understand that topic in itself...something to do with the shape of the compression chamber, or piston head, or somethin?) BUT, where did the term come from? Did the death star have a hemi or wat?

Secondly: Defintion of a racing term, to drop your tranny, or gears or something when racing. all i know is its a good way to req a tranny overhaul fast.

Thanx!