So after the exhaust, the stereo also sounds much better in the 7.5? Surprises keep on coming!
Are you maybe located at the south of Sweden? (this would not be an explanation of the better sounding exhaust or audio of-course
)
HAha, yes i know. My subject are little bit funny...sorry....
No from the middle of Swede and full of surprises.. 
This weekend a will do my first roadtrip, after that i will come with more
experiences

But seriously a have got message from another Mk7.5 owner that experiencing the same..
Oh, I don't doubt it although I think the Dynaudio will be still hard to beat. As for the exhaust it should be easy to find out by cross-checking part numbers, I might have an access to that, just out of curiosity.
Last Sunday me and around 30 other Clubsports were at "Clubsport driving experience" at Mantorp Park near Linkoping, organized by VW Sverige to show CS owners the potential of the cars and teach a few things about performance driving, amazing event and if you knew i think you would have been welcome. There was a facelift R participating with us so you wouldn't be the only outsider!
If you ever come south, pm me and we can do some 7.5GTI vs CS "comparisons", i obviously mean build quality and styling wise

Take care!