These 5.25 coaxial speakers are pretty good, they sound only slightly better than the stock bose speakers I replaced them with. The lower end, in fact is much muddier than the stock speakers, the highs on the other end are definitely brighter as the stock speakers have no tweeters. To be fair, these are slightly smaller than my stock speakers and I am running off my head unit(pioneer AVH-X5800BHS). Part of my step upgrade plan. Front stage is next along with an amp. What I did to compensate for the bottoming out is this; I moved the fader slightly more to the rear(where these kickers are), set the rear high pass at a 160 hertz cutoff with a maximum slope(-24db) and set the front(stock no tweeters) to cut at a much lower frequency with a lesser slope(-12db), for now this seems to put the overall soundstage at a satisfactory setting. I guess i was expecting a miracle in sound transformation after dreaming of replacing the rear for so long. Keep in mind that these are moderately priced speakers, that being said, the value of these speakers make it a welcome addition. My final thought; if budget is a concern, and you understand maximizing your sound stage as well as the limitations of size(5.25 can not move a lot of air) than these speakers should fit the bill. If you just need a brighter upgrade to stock these are perfect.
Pros: Easy install, much brighter than stock, will almost fit anywhere, 75 rms and a decent price.
Cons: limited lower end performance(5.25 and polypropylene), bottoms out at about 160 or lower unamplified.