Yes you need adapters if you want to utilize the factory wires and amp. system. Search for car stereo adapter, car stereo conversion kit, etc to get an idea of what you need.
Some are mfg. specific whereas a "Sony to 87TC" might be different than a generic adapter.
Webs like TuneTown.com, Crutchfield.com and 100's of others have these available relatively cheap.. $10 to $30 for the plugs. Shop around.