The 4 categories are:

Horrible brands – avoid these brands at all cost, they are a total waste of money.

Entry level brands – good for the first time car audio enthusiasts, you get a great sound for a cheap price.

High quality brands – these are more expensive than entry level, but not ridiculously expensive, since you get execellent sound that will be louder/cleaner than entry level brands.

Competition brands – these brands are the mother of all brands, prices are very expensive but if you can afford it, these are the brands that win sound competitions at car shows.

HU = Head Units
A = Amps
SW = Subs
Sp = Mids/Highs
M = Multimedia
All = Entire Line

Stay Away

American Pro (All)
Audiobank (All)
Blackmore Mobile Electronics (All)
Blitz (All)
DHD (All)
Diesel Audio (All)
Kenford (All)
Kole Audio (All)
Legacy (All)
Majestic (All)
Performance Teknique (All)
Phase Linear (All)
Pyle (All)
Pyramid (All)
Rockwood (All)
Sherwood (All)
SPL (all)
Solid Audio (All)
Sound Storm (All)
Street Edge (All)
Ultra Linear (All)
XFile Audio (All)

Entry Level

Alphasonik (All)
Alto Mobile USA (All)
Alumapro (All)
Ample Audio (All)
Audiobahn (All)
Audiopipe (All)
Audiovox (All)
Autotek “SS Series” (All)
Bazooka (All)
Blaupunkt (All)
Boss (All)
Bostwick (All)
Cadence (”All” tough decision just shy of high quality)
Cerwin Vega (”All” except Strokers which go in Comp’)
Clarion (A, SW, Sp)
Clif Designs (All)
Concept (All)
Coustic (All)
Crossfire “P Series” (SW)
Crunch (All)
Cutting Edge Audio (All)
DB Drive (All)
Diablo Audio (All)
Digital Audio (All)
Dual (All)
Dub Mag Audio (All)
Elevation Audio (”All” except EX Series (SW) which go in Comp)
Emerson (All)
Harrison Labs (All)
Hifonics “Zues Series and lower” (All)
Hollywood Sound Intl. Corp (All)
Infinity (All)
Interfire (All)
JBL (”All” except ??? Series which go in Comp’)
Jensen (All)
JVC (All)
Kenwood (”All” except Excelon series which go in HQ)
Kicker “Comp/Comp VR” (SW) “RS Series and under” (Sp)
Kove Audio (All)
Lanzar (”All’ except Opti Drive series which go in HQ)
Lightning Audio (All)
MA Audio (”All” except larger/upper model HK Series amps which go in HQ)
Matrxx Audio (All)
MB Quart (SW)
Memphis “PR Series” (All)
MTX (”All” except 9500 Series (SW) which go in HQ)
Niche Audio (All)
Phoenix Gold (SW)
Pioneer (SW,Sp,A)
Planet Audio (All)
Polk Audio (All)
Power Acoustik (All)
Powerbase (All)
Profile (All)
Rockford Fosgate (”All” except Power Series which go in HQ)
Sanyo (All)
Scosche (All)
Sony (All)
SoundStream (All)
Swiss Audio (All)
US Acoustics (All)
Visonik (All)
Xsite (All)

High Quality

A/D/S/ (All)
Adire Audio (All)
Alpine (All)
American Bass (All)
Ascendant Audio (All)
AudioControl (All)
Audison (All)
Avionixx (All)
Boston Acoustics (All)
Brax (All)
CDT Audio (All)
Clarion (HU, M)
Critical Mass (All)
Crossfire “W Series” (SW) “VR Series” (A)
Crystal (All)
Diamond Audio (All)
Directed (All)
DLS (All)
Dynaudio (All)
Earthquake (All)
Elemental Designs (All)
Eclipse (All)
Focal (All)
Fusion (All)
Genesis (All)
Helix (All)
Hifonics “Brutus Series” (All)
Image Dynamics (All)
Incriminator Audio (All)
JL Audio (”All” except lower W series (SW) which go in Entry)
Kenwood “Excelon series” (All)
Kicker “KX/SX Series” (A) “L5/L7″ (SW) “SS Series” (Sp)
Lanzar “Opti Drive” (A)
MA Audio “HK2000/HK4000″ (A)
Massive Audio (All)
MB Quart (Sp)
McIntosh (All)
Memphis (MC Series) (All)
Milbert (All)
Morel (All)
MTX “9500 Series” (SW)
Nakamichi (All)
Orion (A,SW,Sp)
OZ Audio (All)
PHD Audiophile Sound System (All)
Phase Evolution (All)
Phoenix Gold (A)
Pioneer (HU,M)
Powerbass USA (All)
Precision Power (All)
QAS (All)
RE Audio (”All” except MT Series (SW) which go in Comp)
Rockford Fosgate “Power Series” (SW,A)
Seas Lotus (All)
Sinfoni (All)
Treo Engineering (All)
TRU Technology (All)
Tube Driver Blue (All)
US Amps (All)
Xtant (All)
Zapco (All)

Competition

Alpine F1 (All)
Atomic (SW,A)
Autotek “MM Series” (All)
Cerwin Vega “Stroker” (SW)
Digital Designs (All)
Elevation Audio EX Series (SW)
Hifonics “XX Series” (All)
JBL “JBL/Crown Series” (A) “G TI Series” (SW)
Kicker “Solo X” (SW)
MMats Professional Audio (All)
MTX RFL (SW)
Pioneer TS-W5000SPL (SW)
Rainbow (All)
RE Audio “MT Series” (SW)
Team RF (SW)