I purchased these speakers to replace the rear speakers that I had blown in my car. I decided to go with these due to the relatively low price and high peak power handling of 250W.
The installation process was a bit tedious because the mounting clips included were too small for my car (2000 Honda Civic LX). I made my own retaining clips fairly easily with square pieces of plastic and screwed them in from the bottom of the speaker mount.
The sound quality of these speakers is great. I have a 50WX4 cd player and it powers the speakers well without an amplifier. The bass is very powerful, and can easily vibrate my chair and shake my rear view mirrors. One of my favorite things about these speakers is that when driving at night, all the lights in my mirrors bounce to the rhythm of the music. The highs can be a bit "tinny" but if you know how to use your equalizer on your head unit the tinniness can easily be remedied. I listen to a lot of electronic music so the bass provided by these speakers is fantastic.
Overall these are great speakers at a great price, I love them! I will soon be upgrading by front speakers to Alpine type S as well.