It might not sound bad, but you might be missing a few notes unintentionally. If your goal is great sound and a strong front stage, and your mids/mid-bass have to pick up a bunch of that punchy bass. In a previous install, I ran my mid-bass down to 70hz or so, and had the sub coming in around there. It was my best sound quality build ever, the car was deadened tremendously, and the front stage was picking up almost all of the the music, outside of the deepest of notes where there was a sealed sub in the hatch area, where overall space was fairly close to your car.
With the scions, I know they need some deadening work for sure. If you can load up that hatch area, the doors, and a little bit of the floor under the front seats, it will go a long way to improving the performance of your system.
(side note, this topic shows why the SSA forums are still the best for this)