Sorry to bring this up again but just been in a 67 Plate Tiguan. SEL Nav model with std stereo. Both the owner of the Tiguan and I agreed the Audi system is vastly superior to the Tiguan. Night and day was his comment. Subjective I know but I think yours must be faulty. Some speakers or an amp? Take it back!Was a 2011 LCI 'edition' E91. Pretty sure it was the standard set up. Never sounded flat in the middle like this even when new.
Mini cooper D also has always sounded better as does Tiguan.
I have all 3 cars on the drive (mini, Tiguan, and A4) - just spent half hour again fiddling with the bass and treble whilst playing the 'attack of the grey lantern' remaster/reissue. If you know the album you'll understand why this is an excellent test card.
Let me assure you, I am not wrong. If you need to justify your purchase option by convincing yourself that all you read was accurate then fine. Knock yourself out. I have no such desire and would advise anyone who is likely to be bothered by substandard sound to consider upgrading.
Sadly my car allowance would not stretch any further than a sline/tecpack/20k and a Tiguan/SE/8k.