1) My 118TSI has done 29000km and I did think it was a tad louder than normal from a very cold start but that quickly disappears.
2) Can't say I've heard anything like that
3) I've noticed this too on my car. Especially when I'm reversing slowly and go to brake a tad harder than I should, it makes a sound like it's grinding. The car have just been serviced and I haven't noticed it again though.
4) Mine's DSG but I don't know if the sluggish-ness I'm noticing is the throttle lag? (Sorry I'm new to car so I don't know if I'm talking poo poo )