Audi A4 stereo Fault

[shoolhouse]

Hi All i'm New to the site and this is my first post,and i think it's one that would have been posted on here many times before.
I have a A4 Avant 2000 TDi with a faulty concert radio cassette(volume control fault as normal:().
OK i don't want a cassette anyway!,so time to upgrade to a cd unit,looked on good old ebay:D and found lots of Audi concert cd units.
So will these fit with no problems??.
Mine does not (i think?) have a Bose system.
Any:1zhelp: would be great.

[rhysdavies]

It's likely to be a Blaupunkt system - correct me if i'm wrong!

[shoolhouse]

yes i think it is because the old radio unit is a Blaupunkt.
Does this mean i can only use the some make of Audi cd unit?.