Nice to see talk about sound quality. I have not read all of the comments extensively but i would like to make an input. Forgive me if i am wrong, lmao. Most SQ champs use components in their system because of the active crossovers that come with these components. I have never actually entered but i believe you can use any kind of equipment u wish. It's all about achieving the cleanest and most realistic sound your system can produce. That is to say your system must perform as a live band or orchestra when in operation. The ideal way to achieve this is settings parameters. You must be able to set you highs, high mid, low mid and lows properly in each audible range. Therefore you need tweeters, speakers that produce good high mid, also other speakers to produce low mid or mid bass, and offcourse your bass speaker, which is not always necessary in Sq systems. From my point of view a good deck with at least a 6 or 7 band eq is necesary, doesn't matter which brand, what matters is that it has a high preout voltage to drive your system,i.e 4v preout and higher. Preamps are not necessary either but can be used when the deck's eq is not so advanced. Next you must have a crossover which seperates your music into highs , mids and bass. I recently saw a crossover product from taramp which splits into low, low mid, high mid, and highs, which will be perfect in a Sq system. I am sure there are other higher quality crossovers that are 4 way as well, memphis, kicker etc.
Setting your system is key in winning a Sq competition, you must be able to hear each instrument in the song clearly, you must have a good ear. I think the trick is to set everything seperately, and at a maximum of half capacity, always have more power than necessary, and speakers that can take more power, i.e set music away from distortion limit. I hope you understand what i am trying to say.
I have been in car audio for years and have always been fascinated by it. For me the best brands for sound quality are alpine, jbl, jl, rf, orion, boston acoutic and even clarion, my favourite is phoenix gold, which amazes me up to date. Other brands can be used effectively as midrange like 18 sounds, bnc, rcf, das etc. I am currently intrigued by SQ, just dont have the big bucks to rally with the big boys. Btw nice thread nirtime, looking forward to more discussions like these. Peace out