A4 got louder & lost boost

[Rocknfella]

Hi guys. As title says, I've got 2002 A4
While ago noticed engine started work louder, especially when accelerating (way louder). Also noticed it's not so powerful.
Fully serviced 5 month ago incl cambelt & water pump change.
Have any ideas? Based in Leicester

Thanks

 

[Slinepete]

What engine is it

 

[Rocknfella]

2.0 Petrol