Speakers, 2002 Audi A4 Avant

I have a 2002 Audi A4 Avant (Wagon) that has blown speakers.

I plan to purchase and use eD speakers.  I definitely would like to replace the woofer.

It is worth buying a kit to get bigger speakers up front? 

I am happy enough with the stock Bose Symphony system and I don't want to lose the functionality of the head unit. (not that it is great...but I am not in a position to replace the head unit right now)

I want to put in an eD 12 inch woofer and need to know if it would be better to have a dedicated amp or just replace the factory woofer and allow the factory amp to power it???

Does anyone know if it is hard to replace the factory sub with a new sub?  I know there is a size difference so some mods are required.  Most important is whether I can use the factory amp woofer output to power a bigger woofer or do I add a dedicated amp for the woofer? 

do you think the factory amp is good enough for the main speakers?

I am not sure how hard it would be to keep the head unit and replace the speakers and amp.  I have a Helix 5 channel that i would love to use but I don't want to lose the functionality of the head unit.

any idea of the front speaker size?  I keep seeing references that this car uses 6-3/4 in the front door but the grill looks more like a 4 inch to me.  might have to strip the door down.

thanks for the info thus far...

Yes, you can use the factory amp to drive the speakers.  You're only upgrading the sub, correct?  Be sure to disconnect the factory sub when you do all this so you don't get any wierd cancellation issues.

If what you are saying is true and the amps are on the speakers up front, it bothers me a lot more because I was assuming one of the front speakers was blown (though it does act and sound normal at times...like a bad connection).  If I don't have a bad connection, it could possibly be the amp on speaker.

This brings up an interesting dilemma...if the head unit does have an rca out on the back, do I run new cables and use my Helix 5 channel to power the system or do I opt for the "expensive" adapters and replace the main speakers with MB Quart (or the like) and only worry about replacing the sub.

thanks for the info!

I have been out on the Audi forum and there are guys out there that swear there are RCA outputs.  I don't know because I am not willing to tear the dash apart.  I am now past the days of 5000 dollar systems.  I rather be able to take my kids fishing!  Anyway, I think the head unit is fine.  I just have a front speaker that is troublesome, especially when it is cold out.

I have used the eD woofer(s) for quite a while.  I am not interested in trying to achieve high SPL levels and the eD woofers have been great for me and the installs I have done or seen.  If there is a woofer for the price that is more effecient and provides better performance, please share.  I am open to different manf.

I do want to keep the head unit.  I need to do more research on those front speakers so I can determine if I can easily replace them or if I need to go out and find another set of Bose.

Also, since I have read about the built in EQ on the head unit, I might experiment and see if I can clean the sound up a bit through the midrange level...

thanks for the info!