Please go to this website:
http://www.sonicelectronix.com/
These guys can tell you which systems will fit your car, which harness to buy, which trim goes with your car etc etc. i got a brand new stereo for $60 and that included the harness and free shipping. they also gave me a years warranty on top of the manufacturer.i really thought i was dealing with some scam artists from china for a while. but they are from the good ole USA.
I just replaced my factory stereo and they were amazing. i am not getting paid to say this. i really mean they knew their stuff.
this is just one of the many they got
http://www.sonicelectronix.com/item_77236_Boss-BV9356.html
Anyways , if you do end up buying something and need help with the harness wiring please do PM me or post here and i will be glad to guide you with whatever knowledge that i have.