Theres actually 3 options on the plate here:1) compression
2) cone
3) cone with horn.
I picked up the PHL 6.5 inch 1660 and used it without a horn. There is a large difference is power required at 97 SPL for the PHL 6.5 compared to the 105 for the Eminence top horn. With a conical horn mounted the PHL is actually a little stronger than the Eminence horn. It's very close though, therefore easier to balance. I found the sound stage better defined with just the cone though.
Power is not a concern for me since my house can shake all night with any of these options.
Someone's bound to say it sooner or later. Different people like different sounds. It's too bad it isn't easier to get together for a "sound-off". Lima was about as close to that as I've gotten. Cheers to Mike if his ears are on. They were good events.
Hearing is believing.
Grant.