Warning - this applies to cars with sq in mind, spl subs will wreck most of the following theory. Also, cars with rear fill over 1/2 the power of the front wont benifit as you've already killed your soundstage. If you had a 2-way vs. a 3-way in 6.5" form, one could sound better; but this is design derived and not concept derived(aka its not solely based on how many speakers you have). If all you want to know for any system is: what is better, 2-way or 3-way? Neither is inherently better, it comes down to design. The rest of this post examines how an effective 3-way system changes a car's sound/soundstage. Begin. Looking through other threads, a lot of people are caught up on more/bigger is better. I just want you to realize this isn't always the case. Until they manufacture 8" 3-way systems, the basic concept of utilizing more speakers is lost. The whole point of 3-way is to keep more low freq in front of you that can be localized and keep speakers within practical freq response domains. What we want is a clear image and presentation from the front of the vehicle, so we would like to shove two 15's up front for stereo bass, but this is impractical. But if we could manage two 8's with enough displacement, would could keep as much bass up front as is possible. Instead of 2-way(w/sub of course): 1" tweeter - 2.5-3k to 18k+ 6.5" mid - 150-200hz to 2.5-3k x" sub - ?-150hz with an 8" up front, we can change to: 1" tweet - 3-4k and up 4-5" midrange - 500-600hz to 3-4k 8" midbass - 50-80 to 500-600hz sub - ? to 50-80 We've made it easier to: 1) find tweeters that don't go so low, very helpful 2) change midrange size to acheive a higher cross-over point from tweet to mid 3) our freq response from the front is extended down to under 100hz, depending on driver and enclosure 4) even if the car rattles, it will hopefully rattle in front of us so we dont hear so much noise from behind Even if you had an awesome 6.5" with lots of throw, it wont extend as low as an 8" with the same effort. This is even more apparent when the same awesome performance/technology is given to the 8". (i.e. check out adire audio's 6 and 8 inchers with more xmax than some 10/12's.) Does that help?