If you strap it to your roof and blast "Posse on Broadway", you'll reap all the audible sensations of having a V8, while adding massaging seats and girlies that need a ride, but with no room inside, they'll have to stack on the hood. With your muffler draggin' and suspension getting weak, you'll now need a lift and that drains the bank.
I'd just put something in the stock location and call it good.
So what you have linked isn’t anything special — it’s just an external enclosure with a sub. Those are readily available all over - a lot of folks throw them in their trunks
You will need an amp to drive it
They can sound great - sound quality varies a lot, the box and speaker selection matter and they have to work together, so a pre-engineered kit like the one you linked is not a bad option
The downside is that the Bronco doesn’t really have a trunk to throw it in. You can certainly throw it in the back, or buckle it in the back seat, or whatever you want to do with it, but it’s always just gonna be hanging out there. You could secure it with bolts or something but you are on your own to figure that out. They are commonly stolen items as well, so if you have a soft top…
The custom JL that fits in the OEM enclosure space is much more expensive. There are “tailgate” enclosures that bolt to the inside of the tailgate and are a bit more secure, and a good bit less than the custom JL (although still somewhat pricey). There are roll bar sound bars you can mount - but it makes looking out the back glass difficult. And there’s the standard “upgrade the OEM speaker” route but you get limited in speaker size that way
Every choice has pros and cons and cost. If you are ok with this just hanging out in your cargo space, and installing an amp and running the wiring to it - yeah, these external enclosures (not sure about this particular one) can absolutely sound great, and can last between many vehicles. But it is gonna eat up a lot of that cargo area, and be an obvious and tempting target unless you take action against it
If you have a relative budget in mind - throwing that out here could help us give you some other recommendations. You can upgrade the speaker in the OEM enclosure for a bit less if cost is really sensitive - but you still need to consider an amp