Thanks, Dave!
I linked the new sound folder to the -200 series model only, then boarded G-ASJG* for a trip from Tallinn to Moscow.
In case someone will find here on the search for details I allow myself a quick review:
-> Most of the cockpit sounds such as altitude alert, overspeed and stall warning/stick shaker are still the same *(don't worry it was a FERRY flight...

)
-> Flaps retract and gear lever sounds are replaced - but that isn't worth to tell
-> Adds sort of a rattle-sound when you're on ground at higher speed
Outside engine sound is great (quieter, more of that Spey-whistling)
Inside sound ambiance is much quieter, much more avionics, less engine - very realistic
APU sounds great (incl. great spool-up)
Spooling sounds at engine start are fantastic!
This is actually the best part of the sound set and the biggest reason to replace the original.
However there's a few minor issues I discovered:
my sound card obviously isn't fit enough: engine sounds are changing "stepwise" - and that really spoils the fun!
reverser stops abruptly (only in outside view mode)
rattle-sounds are also audible in outside view mode
All in all it's pretty hard to decide what's better. The biggest change in the sim experience actually is that the engine sounds are much quieter, which makes a real difference and you have to get used to it - but there's certain aspect of relaxation in that. Personally I'll stick to the original for I'm annoyed by the "stepwise" changing of the engine sounds. However I'll leave the package with the -200 series so I know what aircraft to select whenever I want to enjoy a realistic engine-startup...
All the best,
Nick