2003 a4 conversion to bose sound
 

Hello,

I just managed to buy myself a 2003 A4 avant with a stock sound system that is not bose. Looking for everything, this escaped my attention and sucks big time. Here's the question:

- is the head unit the same than the one for a car fitted with the bose system?
- let's say i bought all bose speakers on ebay, is all the wiring the same so that i can expect to plug and play?
-are some speakers the same? i.e. tweeters/sub-woofer?
- in my old 1996 A4, I had an amplifier unit in the back. Would I need to add that, or is that in place now?

bottom line... do you think it makes sense and how much am i looking to spend (money/time)?
is there a better solution if I'm not looking to drop a crazy amount of money and just want a decent sound system.

Any input would be greatly appreciated.