This article is from the Car Audio FAQ, by Ian D. Bjorhovde (ianbjor@mobileaudio.com) with numerous contributions by others.
Most of the time, you will either buy from a local dealer, or from a
mail-order house. Buying from a local dealer can be good because you
get to deal directly with a person: you can show them your car, ask
specific questions, haggle prices, get quick service when there are
problems, get deals on installation, etc. But there can also be
advantages to buying mail-order: generally cheaper prices, sometimes
better service, etc. In either case, you should always check prices
before you buy, inquire about warranty service, and ask about trial
periods.
 
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