Get 2 sets of
Crystal CSx570 speakers for drop-in high performance (cost $80/pair). It uses an outboard crossover (directs highs to the tweet and lows to the woofer) which is easy to install with the speaker.
A good crossover section is imperative for clean, precise sound. "Cheap" coaxials just put a cap on the tweet to block the lows and let the highs roll off on the woofer. So, you've got two drivers producing an overlapping set of frequencies which muddies the sound.
Don't get caught up in the round versus oval thing. It's really not important. Any difference between the same motors being used on different cone shapes (provided the same surface area) would be inaudible.
