I have a new Malibu 247 on order and I am looking for a good tower set up, my concern is the head room. I know that I would have to duck under, however my question is if I mounted 4 MB8's on the side will they sound as good as the 3 some set up? They would both have adequate power either way. Thanks for the help.
You don't want 4 MB8's, the MB8 is a midbass companion to the Pro 80 or Pro 60.
On your Bu I believe you have two good options a Pro-60/MB8 setup or a threesome: threesome has three high frequency drivers compared to two in the other setup. Personally I would go for the Pro-60/MB8 solution in the stock locations. Check with Wetsounds to make sure they fit.
My buddy has 4 Pro-60s, I have Pro-485's, and I have heard several threesome setups. All sound very good. I recommend the 60's and the MB8's, I think four 80's look crowded. Not a huge difference sound wise, a few bucks less.