I am the owner of an 03 EX V6 sedan. I recently replaced all four speakers in the vehicle. In the front I went with a 6.5 coaxial Polk Audio and left the stock tweeters in tact.

The rears are also Polk and they are 6 x 9. Factory fronts didnt look too bad but the rears were absolute garbage.

In total spent about $250 including install and the sound difference is simply night and day!