I'm repurposing a set of 6 Ohm 2-ways from my early 2000s Philips HiFi system. Each speaker has a 5 inch sub and a 2.5 inch tweeter. The system was advertised as "100W Music Power" and "2x50W RMS Stereo" on the brochure, but according to the manual the internal amp delivered 2x45W FTC @ 6 Ohms.
The manual says nothing about the speaker's maximum input power. For comparison I know the maximum input power of a modern 6 Ohm speaker like the Sony SS-CS5(M1) is 100W.
I plan to use a Topping Mini 300 to drive them and these are its specs for 4 and 8 Ohms:
140W x 2 @ 4Ω THD+N<10%
125W x 2 @ 4 Ω THD+N<1%
85W x 2 @ 8Ω THD+N<10%
65W x 2 @ 8Ω THD+N<1%
How do you know if an amp provides too much power? I was always told that to worry about a weak amp not a strong amp.