I have a sound bar from a YJ in my 7. I installed aftermarket speakers as the OEM were junk. Prior to the sound bar, I had those wedges that install behind the front seats and those were too muffled. It's one thing to muffle low bass notes, but you really shouldn't do that with mids and highs.
Also for mounting, I ran some screws through the mounting tabs on the roll bar and the roll bar. That thing isn't going anywhere soon....
P.S. I have a YJ roll bar in my 7