The speakers are Bose, just not the tweeters as already said.
Yes, Bose actually complicates the upgrade process, so by speccing it you need to ensure you're happy with it, which many strange people seem to be.
With non Bose you can upgrade different bits at different times, so alot easier all round.
You can use the stock speaker wiring but you'd need to locate any crossovers in the door panels and bypass the wiring to the tweeters. Rewiring the doors is a massive PITA, so I'd use the stock wiring especially if you're running it from an amp already in the boot.
Sorry I didn't realise Audi have switched back to Grundig as an OEM supplier (didn't even know Grundig still existed!)