Jerry,
You mention adding sound systems. If that be the case, then the sound system will come with a speaker as a component of the package. However, Sierra and PH supply less than top quality speakers. If you go with the Phoenix system it will come with a high quality speaker. To just purchase speakers try Radio Shack. They sell a brand, Realistic, that is an automotive type with a heavy magnet that produces good sound quality and range.
JD - The VA One