i have a writeup for the front mount...and a cuple ideas/links to help out in the area...
basically since our cars are fwd, the engine rocks back and forth when revvd... on a manual 2gnt, it is easy to break em loose in first, and the tires will hop up and down....
sumthin about inertia, and our suspension...
do a lil search on motor mounts, and u will learn more...
i never heard anything bad about em, actually, the worst bein the increased vibration at idle, w/the a/c on, and in the upper rpm range...
good luck either way.. definately a good mod imo...werth 20 bux