I may be too late, but have you considered component speakers instead of coaxial?
I take it your Civic's stock speakers have a woofer in the door and tweeter in the dash, unless you have the bare system. I personally recommend you try out a component set, it may raise your soundstage.
One fair thing about your '07 Civic, is that the dash speakers are fairly far out - which can help if you where to decide to mount the tweeters there.
Sony XS-GS1720S at sonicelectronix.com/ can be found for $180 with a $100 e-gift card. I know that's over your budget, but these new GS series speakers are nice for the money.
Some other speakers of notice:
JBL GTO608C
Pioneer TS-D1720C (if they fit)
Also, seal your doors and address any resonant issues with some dampening material. THIS right here is the key to better midrange/midbass.