yea the skid plate has to come off, its fairly simple to do anyway, just support the tail shaft of the tcase, and remove the 3/4's bolts, take off the nuts, and for the one bolt, you will have to get a wrench on the nut on top and hold it while you crank off the other bolt. That sounds ocnfusing but once your under the jeep actually doing the job, you will be like oh so thats what he meant.
as for the sound bars, i have a 6 speaker on, replaced the speakers in my dash, and put diff woofers in my soundbar. added a set of tweeters to the front, and put a 10' sub in the trunk, i am very pleased with my sound system.