Hi, I have a B6 A4 Avant with the OE Symphony HU 6 disk changer, radio + tape double DIN I believe. The sound quality is rubbish. I have just upgraded the front speakers this WE, but it doesn't seem to be enough. I put in a pair of KEF KAR 6.5 woofers with Infinity Ref tweeters, the original KEF tweeters got destroyed in storage :-( I had to make some spacer rings from ply, as the original noise maker had a integrated mount. I am after a sensible upgrade plan, but I'm not sure where the major problems are.I did the front speakers first as they were cutting out occasionally, due to poor connection probably and I had the speakers from my old golf. I'd like to keep the original HU, it looks good in the interior and works with the DIS. Is it a major limiting factor ? Is it the internal amp that is poor? I've read it does have preouts ? Is that 5 preouts? (F,R & sub) Is it worth replacing the rear door speakers? There is a tiny sub and amp behind the driver side rear quarter panel. I assume it is worth replacing that ? am I right in assuming I can take the signal feed from the input of that ? I have a minimal budget, as I have kids and wifey. I like the idea of AndyMac's stealth sub as a big sub box or even a small bass box in the boot, as it will get in the way of the babies stuff. Cheers!