Good score on the Formula 5's. I worked in a high-end audio store part-time while in high school in the mid-70's. We sold everything from Klipsch to JBL to BIC speakers. I had the opportunity to listen to all the top speakers of the day by switching from one set to the next using the same audio source (usually a quality amp and turntable). The BIC's, particularly the Formula 6's, outperformed everything we had except for the top Klipsch speakers, which were four to five times more expensive.
I started buying equipment and continually upgraded as my budget allowed while in college, ending up with a clean-sounding, powerful, DC Integrated amp from Kenwood, Formula 2's stacked on Formula 5's, and a quartz locked direct drive turntable from JVC. It still outperforms anything my friends have bought recently, including a high-dollar, surround sound system that a friend recenly installed for big money.
The key to making the Formula's sound good is to feed them plenty of clean power from a quality amp. eBay has amps available regularly. Look for a Kenwood KA-7100 or KA-9100. After 30 years, mine are still going strong.