Elipsa specs are as follows:
FREQUENCY RESPONSE
35 Hz - 30.000 Hz, tuning ports included.
SENSITIVITY
91 dB SPL (2,83 V/1m).
NOMINAL IMPEDANCE
4 ohm.
POWER HANDLING
50W - 300W, without clipping.
I have Strads and my Pass XA60.5's are enough for me power-wise but they do need more juice to really come alive and get controlled. I do recommend going up to the XA60.8's, at least, unless you play your music low. Strads and, I am sure, Elipsa need more juice. Even the recommended watts are at least 50wpc, so go up a little to be on the safe side.