As an owner of the XA30.8 I would say the 150.8 is your best choice for those speakers. Although the 150.8 leaves Class A at 13W it delivers 150 watts into 8ohms and 300 watts into 4ohms. The XA25 and 30.8 (while hugely underrated on power) are really meant to be paired with easy to drive higher sensitivity speakers. I think the JA speakers aren't terrible difficult to drive as they may not dip below 6ohms (?). Last time I talked to a JA rep at a show he indicated they usually recommend an amp with at least 50 watts.
