Cool I will look at this one.I like the jbl flip 4 or the jbl charge 4. The flip 4 has a better mid to high range while the charge 4 has better lows but not quite as good in the mid to highs compared to the flip 4. The charge 4 overall gets louder so that is the one I ended up keeping. I've used both of them in a truck I used to drive for work since it didn't have a radio. That was a big truck that was way louder than any car and it sounded pretty good. It is pretty close in price to a new head unit so I would probably go that route unless it's not an option.
This. I have 3 of em. They are great.
Actually works very well. I'll probably secure it down with some tacky velcro soon.