I used a pair of RF-7's with my paramounts and loved it. I wired the OPT's for 4ohms. It did need to get turned up a bit to get enough current for the woofers to open up.
They paired well the S.E.X amp, but obviously with less volume. More than enough for a small room. The RF-7's had 102db efficiency. The amp was wired for 8ohms.