As title states one of my speakers have gone and I saw that some Audi a3's have the Bose upgrades and I was wondering if they fit because I would love to upgrade my crappy speakers cheers

Need to be careful of the mounting depth due to window winding mechanism behind speaker. I suspect the Audi A3 speakers wouldn't be worth the effort unless you had them sitting on your shelf.

The Bose ones are an upgrade kit related to a stand alone amp. They are an arse to work on - especialyy if you try and retro fit them into another car without the same amp!

Forget Bose, they aint as good as hyped and quite expensive. Just get some aftermarket speakers, ive got vibe which I love but there are plenty of awesome components out there, Rockford fosgate, polk, infinity, pioneer just name to a few