Some good advice there from snoopy, but before you jump in too deep, it might be worth simplifying things a little!
Your front components are probably OK, but as said above, the mid mounting and tweeter location are key, and can make a huge difference to the overall sound of the system. Your headunit, being Clarion should also be fine, although I've never heard that particular model.
I've never heard praise for anything made by in-phase - so you may want to consider a sub upgrade. You also don't mention the enclosure type - is it sealed or ported? Was is made specifically for those subs, or just knocked together?
Also, if you haven't got an amp for your front end, you will also realise a big difference in volume and quality if you fit one.
To summerise, stick to front comps and a sub (or subs) in the correct enclosure, and feed them the appropriate amount of clean power. This is all that most SQ competition winning installs use. Combined with the correct installation and setting-up, you should end up with a respectable sounding system.