Agck! It's you again.
Well, if it's got all the goodies in one unit, it's called a Double-Din.
you should probably be able to tell just by looking at your unit if its DD or not. Usually, DD's are twice the size of a normal single-din unit. If what you have, and most likely is a DD if it's OEM, then the whole cd player/cassette/radio is one whole unit.
If you buy a new cd unit, it will 99.9% of the time come with a radio. However, to get a cassette player along with a cd player in the same unit, you need to splurge on a DD unit.
Since you're in the situation where you most likely have a DD unit, there would be no way for you to keep your working radio/cassette player and swap your cd player.
So, might as well pay for a new DD unit if you want the best of both worlds.
www.crutchfield.com will answer most of your questions.
