Mach 5 Audio, SoundSplitter, Ascendant Audio, TC Sounds
AMPS: Zed, Zapco, Arc, Audison, Sundown, the Zed amp's are some the best SQ amps out there for the money, and add some sundown for your amps, very beefy system. Or go old school: Soundstream Reference, PPI Art & PC series, old crunch, a/d/s (mids and highs amps), old Zed amps, old optidrive lanzar, yes I said lanzar. I have a PPI PC4400, sound quality is outstanding, really want an old a/d/s 6 channel pq15? I think was the model. But your right best buy's stereo equipment is pretty shitty except for maybe a head unit.
Mach5 has some unreal deals on there sub line, while there not really SPL subs, the MJ18 sounds astounding for a SVC 18, very accurate. I have installed one on 400w of power, 3.6cf sealed in an suv and it sounds unreal and gets really loud. They are soon going to offer an SPL sub on a budget around 30mm xmax, real nice looking sub.
Ascendant Audio is a great company that is partnering with FI to help with production, but I have a 10" assassin in a small sealed box and it really sounds great, an awesome compliment to my a/d/s components.
TC sounds tc-1000 line is a great bang for your buck line if you can give the speaker some cf. Currently building a tc1000 15 in a 10cf ported box tuned to
16.5hz for home threatre. It has an unreal virtually flat response in a large enclosure.
In my opinion FI, RE, etc. subs are nice but the pricing is starting to become to retail for me.