sony has been around for many years, but there car audio systems have been around for only the past couple of years.
sony makes good HU and good amps. there woofers are worthless piece of junks (no offence to anyone that uses them). if your looking for something affordable and will give you a decent BOOM then i would say go with sony. but if ur someone like me that loves clarity and wants the best out of there money then please read below
i will categorize everything by price range (1) is expensive (3) is cheapest
HEADUNITS
1) Alpine - awesome HU, has very neat functions but to expensive. you can get the same stuff in poineer
2) Poineer/Kenwood - everyone is familiar with these 2 companies. the point of the HU is to let you play with every single setting for speakers and woofers. for that i would say go to poineer. iv used there HU's on all my cars and never have been disappointed. remember the more expensive doesnt really mean the best quality. poineer and kenwood have been in the car audio business forever. they no what they make is the best and i back them in that
3-sony xplod - decent and very affordable systems. havnt really used them but most ppl go for them because they work well and dont hurt ur bank account. a plus side is sony makes good DVD players and anything that works on CD...i would never say there HU suck.
SPEAKERS
1) alpine/fosgate/jl/kickers/boston acoustics - number one speakers for me would be boston acoustics. i have never heard anything as clear as those babies...woow what speakers man. alpine speakers are really good as well. the others are just alrite. i think they are to expensive with not that great quality. if you want speakers its BOSTONS
2) poineer/kenwood - i love the poineer speakers. iv used them in all my cars and i cant find anythign wrong with them. the important thing is to get bigger speakers so they can match with your bass. otherwise you wont be hearing much speaking and only bass.
3) xplod and the others - worthless in my dictionary
WOOFERS
1) Alpine/Rockfard Fosgate/JL Audio/kickers - very very very expensive woofers, but the best and most crisp bass making systems in the market. iv tried woofers from all 3 of them and trust me these woofers will make ur hair vibrate
...however the best part about these woofers is they have affordable models. but once you get greedy and want more bass then the woofers can get very expensive. IMHO if you get a alpine type-x, or a Fosgate T1, or a JL 13W7 you will have the biggest grin on your face. the best part is you only need one woofer and your good to go
2) poineer/kenwood/jbl - poineer makes awesome woofers, kenwoods latest woofers suck, i used to love there older bandpass model woofers but its hard to find them now. jbl is very HOT in the market and i really like there woofers. just try to stay away from there tube woofers which IMHO suck like crap. no tube can make better bass then a proper vented box. jbl also has some new 3000watt woofers which are just awesome, but again you cant compare there clarity to criteria 1.
3) sony Xplod - i no i keep putting it in the 3rd criteria but hey man its just me, i dont think they are still up there in the car audio market. and there woofers, they are complete piece of junk. i have never heard something more horrible then xplod woofers. but then thats just me.
AMPLIFIERS
1) Alpine/Rockfard Fosgate/JL Audio/kickers - again very expensive but offer good power to your woofer. do you need them?? no not really. but remember if you are going to use a strong woofer then you need a strong amp to back it up . you can run a alpine type-x of a kenwood amp, as long as the amp can give enough power to the woofer. if i was to choose amp from this criteria it would be the jl audio 1000/1. its a sick amp and can hold down atleast 2strong woofers. and they arent that expensive either.
2) poineer/kenwood - IMHO the poineer amps suck. its so sad to see poineer cant make proper amps to this day. if you want a proper amp stick with kenwood. they even started making amps with bass remotes so you can adjust bass up front instead of going to the back of the car and adjusting the bass settings. kenwood is SICK IN THIS CRITERIA. if you want a affordable amp with power stick with kenwood
3) sony xplod - i should have put this in the poineer/kenwood criteria because they do make awesome amps, infact i used one temporarly, and it wasnt to bad. however, there is something still lacking in it. what it is i dont no, but there is something.
WIRING
I am very anal about wiring and i wont put a criteria in this. without proper wiring your 10,000aed system is a piece of junk. never try to save money when buying wiring. for me the best wire kit would be monster cabling. they got think/fat cables to make sure you get the best bang for the buck. there are other brands like tsunami and soundstream that make proper wiring kits as well but i prefer monster after trying all flavours of wiring.
CAPACITOR
again no critiria in this either. its something that you honestly dont need unless your going hardcore. a CAP just stores power for the amp so the amp has power whenever it needs it. one of my sound systems used 3 caps and the other had none. if you want to be flashy and show off then getone. but IMHO you really dont need it unless your going big.
if you do decide to get one then stick with tsunami, they are nice and very affordable. remember you can even take the capictor out of your home fan and use it in your car. makes no difference. but if your looking for classy shit then get a soundstream capictor.
1-2farad is reasonable for a average sized system. the bigger you go the bigger your CAP. iv used 8farad and 10farad.
BOX
if your box aint built properly your woofer is gonna through more air and less bass. try to stay away from tube box's which IMHO suck like crap. they dont give bass they just vibrate things. try to stick with ventilated/bandpass/or closed boxes. i would use closed boxes for smaller woofers to get more BOOOM out of it. but for bigger woofers definatly ventilated.
BATTERY
not essential UNLESS you have a crazy 1000000000watt system. i was very picky with my sound system and i wanted it to be powered properly. there is only one battery i would recommend to install and that would be the yellow top ones. i dont no the exact company but thats what they are known as. otherwise you can use any normal car battery. some people have 2batteries in there cars and some have 1. again its a matter of choice and taste.
SOUND DEADNING
why do you need this??? to stop your trunk rattling. the rattling is caused by air produced from the woofer entering between sheets of metal. this can be stopped by appling a sound deadning material like dynamat to cover up those open air spaces that let the air get in between the metal. iv used alot of crap to stop this rattling noise....even sylicon which didnt work
i cant think of anything more that i can add to this. again its a matter of taste and money. the more deeper your pockets go the better the bang is. but if your smart (LIKE ME) you can get the best of all worlds in a more affordable way by studying all the avialable products in the market.
last but not least please do not judge a system by the number of watt's. watt's are nothing, the real numbers are RMS WATTS....
good luck to you all
to keep it banging 
