has anyone done this? any notable improvement?

Very noticalble. I would gut the whole bose system. I did

I'm thinking of gutting the whole BOSE system, but I probably need to pace myself financially.
Hence, do you think if I added just the amp (i'm thinking of the Alpine 5 channel amp [4x90 + 1x300] forget the model).

I heard that the BOSE speakers are self amplified, is that true? If so, which speakers are actually going thru the stock BOSE amp?

thanks guys

If I were to gut the bose speakers and amp, but wanted to keep the factory head unit/changer can this be done?

there are several variations of BOSE setups between manufactures ant the one in the audi is really simple. the dack has a balanced line output on it that it used for both the Bose and non-Bose setups. The difference is the amps and speakers. The bose amp is a cheap IC amp that has some EQ for the car. also the EQ in the amp is another inexpensive way to make the POS amp that they are using sound better. there are some instances where changing things about BOSE is near impossible without doing a complete gut job in different cars. this is simply not the case in the AUDI S4.

By the way in my younger days i was a professional installer and i have about 37 IASCA wins. I have also done 3 car for Noel Lee the owner of Monster Cable. trust me i know what i am talking about!!!

good aftermarket. Also i am sure that you are going to say that the impedence has something to do with it too but it doesn't the only thing that would effect is the AMP, due to the resistance. The problems that you are talking about just won't happen in the case of the 2000 AUDI A4 & S4 bose. Trust me on this one, I happen to know something about it.