Gianluca,
I replaced the ZDZ 40 for a Brison/Revolution52, because of the lack of power and the high vibrations.
Also the Revolution was not to my liking. Last year it has been replaced by a MVVS45.
This engine is really perfect for the model, power wise and vibration-wise. So do yourself a favour and buy the MVVS.
It is a side exhaust and you have to cut the hood, but that is the only disadvantage.
Regards,
Hans