Kanga
It is more burbly at idle (not much though) and a bit noisier when revved - again not much though.
If I'm just driving along normally (you know at 30 like I always do
) then there is a bit more of a boom - not too much but quite pleasant
Jano at Autodelta reckons the exhaust is quite restrictive (along with the intake system) and is in the process of designing some exhaust system for the 159, maybe decatting it.
About the centre caps - I was going to leave the OZ ones but people seem to think it looks better with Alfa ones. What do people think?