Guys - I'm awake 
Correct - the retarder is just sound. You can modify the engine sound blueprint to reduce it or remove it if you don't like it.
You all know I'm a one-man-band. I do the graphics, sound, scripts, documents, testing, marketing, support etc, and I love the support I get from everyone, so hopefully you'll excuse me when my weak point (sound) comes up. I do try - really I do - but it's just always a weak point for me 
There will no doubt be new paint and new sounds pretty quickly - the German (and Dutch) players are always really creative for modifying the models.
There is one really important thing I need to let you know - with everything else that happens during a release there was a miscommunication with JustTrains. You might have noticed their price was a little bit cheaper than all the other stores. If you picked up the train at that price, congratulations! I think tonight the price will be corrected to match RailTraction, Aerosoft, Signalsoft and Treinpunt. It's still a good value - I believe - and I hope you agree. I apologise for the pricing problem but hopefully you all understand by now that this isn't something "suspicious" or malicious. I'm just trying to make sure all the stores have similar competition.
So finally - thanks to everyone who has bought it and is playing with it - it's nice for me to finally see it being used by more than 5 people 