Hey Kent.
The main reason is that someone in the past someone replaced one of the original CTS woofers with a driver from an Infinity, probably from the s series and the sound doesn't match. I have not been able to locate an original woofer to replace it with. So that entails replacing both woofer drivers. If replacing both I had rather have an 8 ohm pair so that I can run them from my receivers along with another pair of speakers. Parts express has some decent 8" 4 ohm speakers but not with the correct values or frame size. My cabinets require an overall frame diameter of 8.25". No easy solution but as I see it my choices are limited to finding a needle in a haystack or converting to 8 ohm and try to stay as close to the sound as the originals. I may only have to change the choke if the other specs for the 8 ohms are close. Maybe I should leave them as is and hope to find an original woofer one day?