I use the model 412 and 415 and yes VERY C4EST EFFICAS.
The noise level in bi-amplification there is nothing wrong with the system.
Whether mp418sp 1 or 2 + 2 sat sat mp418sp + 2 is the top.
A system mp418sp 1 + 2 sat it works very well already.
Before these systems, I would not speak with other brands or system that does not fund the "weight".
For the price it's a bit expensive but it's worth.
I change my system every year and I take the same, that is to say ...
If someone's interested I change the end of February.