Hello dueno, BL9s sound really well and can be found for good prices now. But you must like their appearance too 🤔. Regards, Johan

I took the Bl1 + bl2 route. I am very happy with them. They are a definite improvement. My wife thinks they look much better, too.  Beware, they are a very large, heavy speaker. I looked at the 9s when I did this upgrade (maybe 10 yrs ago), but they were much more expensive and didn't really fit the room. They probably sound the best by a small degree. I have no experience with the 18s, but they could be the best option from a longevity perspective since they are the newest design.