[bmw528i]

I don't know too much about this company, but I think for the rear fill you should look into a 2 way co-axial. I think you will be much happier with the sound quality over the mid drivers. You won't get much bass with them anyway, probably not much more than a regular mid driver on a co-axial to begin with and you will definitely notice the loss of the highs in the rear fill as well. If you are not going to go with a sub woofer you won't get bass anyways. You will hear mids and highs. I recommend a 4 channel amplifier if you go with rear co-axials. Look for something in the 70-100 watt @ 4ohm range. I think you will be much happier with that than rear mid drivers alone. I personally have Polk MMC 525 components front and Polk MMC 525 co-axials rear running off a JL Audio 300/4 and it sounds absolutely fantastic. Even though my Polk's aren't audiophile grade they still sound really good powered off the JL. I had the speakers installed at a local shop originally powered off a Kenwood KAC8402 which didn't provide enough juice or sound quality. I bought the JL Audio 300/4 on e-bay new in the box for $300. Without the sub woofer and additional equipment in my car the setup with the speakers, amplifier, power cable, ground, RCA's, and speaker wire cost me roughly $900 total with installation. I'm pretty satisfied with this setup as it is a quality sounding setup that turns heads.