I've owned the Silverline Sonata II's. Decent speaker (kinda large), but despite it's size, it is lean in the bass and would benefit from a subwoofer (you only need one BTW). Even though Silverline does employ some Dynaudio drivers in their designs, my experience with the Sonata II did not resemble the Dynaudio house sound... and I've owned 5 pairs of Dynaudio's, and still own 3 pair.
The Sonata II's would be a very significant upgrade over your Soliloquy 6.2i's (I owned these just prior to moving up to the Silverline's). However, try to find (or wait for) a used pair of Sonata III's... they are supposed to be more dynamic, full & balanced sounding vs. the II's, and to me, the Sonata III's are much better looking than the II's.
The Sonata II's would be a very significant upgrade over your Soliloquy 6.2i's (I owned these just prior to moving up to the Silverline's). However, try to find (or wait for) a used pair of Sonata III's... they are supposed to be more dynamic, full & balanced sounding vs. the II's, and to me, the Sonata III's are much better looking than the II's.