There are plenty of opinions here..so here's one more. Agreed, the dealer bazooka is not worth $500. Nor is it worth $249. It's not that they are terrible, this one may be, it depends on which line you purchase. I was in a similar boat. I ran an audiobahn a1300hct and two adiobahn aw1006's in my old car. In the tC I just wanted more depth to the music.
Step one - new deck pioneer dehp8600mp
step two - new speakers inifinity kappa perfects front and back - components in front
step three - I added and infinity basslink. I looked into the basslinkt first but found that I would lose the ability to use the folding back seats for cargo room. The basslink offers a 200w rms 10" sub with a 10" passive radiator. I used the remote bass control (gain control) to give more control form the cockpit. Very small footprint that allows 2 sets of golf clubs to still fit in trunk. Here's a link.
Basslink