I have these installed in the doors of my 2000 cavalier Z24 winter beater.
Custom work was required to install due to woofer depth, and I installed the tweeters in pods at top of doors (after several days of listening, I ended up installing off-axis, facing opposing side of car, which sounded best and gave a balanced image with minimal time alignment required from my headunit). Doors are vibration damped with dynamat, and speakers are driven with 120 rms per channel. Head unit is a Kenwood X995. I listen to all types of music, including top 40, folk and rock.
Installed these as a first attempt when looking for an inexpensive improvement over the coax units in the car from the previous owner. At low to moderate volumes, the tweeters are overly efficient and are unbalanced to the woofers (I attribute some of this to my elevated mounting position) and induced listening fatigue fairly quickly. At elevated volume levels, the tweeters get downright harsh and nasty. Midbass is as expected from a 6.5" driver, and only gets uncontrolled at high power levels. I am running them with a 12 db/oct HPF at 60 hz. The tweeters were so tiring that I ended up installing L-pads to drop their output by 8db, which has made the speakers sound more balanced and cleaner. The tweeters still get harsh sounding when driven hard, and I will be swapping these out when I get a chance.
Previously I had used MBQuarts in a few installs back in the mid 90's which is why I started with these, but those older units were much better (and more expensive) speakers. My next trial will be with the PVL 216's, which I recently ordered from Sonic too. In the end, I guess you get what you pay for. Luckily, I love tinkering around with audio systems, and I look forward to finding that elusive combination of affordable quality sound.