I recently bought a 2002 Audi A3 (8L), non bose with a sub woofer in the boot (which makes it half amplified from what i gather). I am hoping to replace the Audi Concert stereo with a bluetooth one (probably this one if i do the self install.. http://www.halfords.ie/webapp/wcs/stores/servlet/product_storeId_11101_catalogId_15551_productId_91 8067_langId_-1_categoryId_212600) but I was quoted a price of â¬100 for installation and additional parts on top of the head unit price. because money is a bit tight i was considering doing it myself and have a few questions... Is this too complicated a job for a novice like myself? which iso adaptor do i need (pc9-401 or pc9-404 or other)? will the rear sub and speakers work with these adaptors? are the cheap ebay versions of these adaptors any good? has anybody completed this installation successfully? if so could you provide some guidance?...step by step or just general. Thanks... M.