Fernando, good choice of new gear..:0)
In this hobby, like Charles1dad says, it pays to try and match gear to other gear that is synergistic with said gear. If you try and put a low efficient speaker with a low powered amp like an SE you will most likely run into the problems similar to that you are describing. Conversely, if you run horns ( typically highly efficient speakers) with very high powered amps, you may or may not get good results either; the amps could be loafing, but the preamp may be way out of its "sweet zone" resulting in again, less than premium sound.
IMHO, the room, the type of music you are looking to reproduce, the size of the room and many other variables should be considered before you waste large amounts of money on gear that cannot work well when it all comes together in: 'your system'. Just IMHO..