I finally got all of my parts in on Tuesday. I picked up a pair of horns from MCM last week, so I was only waiting on PE to send me the inductors/chokes. I assembled the whole thing on perfboard and stuffed the cabs with some fiberglass insulation, removing and adding some until I got enough bass.
First listening impressions last evening were kind of blah. I could see that there was somewhat improved sound, in that the Advent tweeters were never the greatest, so the compression drivers did sound better, but bass was muddy/absent, and it all sounded a bit lifeless. Tonight I sealed around the drivers and played them for a couple hours while I left the room-now they sound GREAT. The horns really give even sound all over my room, which was a problem with the Advents, which only had a really small sweet spot in my crappy house. Now I get great even sound and can ID both channels anywhere in the room. Why the improvement? Maybe sealing up the cabinet, or the fact that I hadn't played the refoamed woofers until yesterday, or the crossovers needed to break in a bit. If it was all about break in, it didn't take too long with these. VERY pleased to have done this.
If you're thinking about doing this and already have pretty decent speakers, you won't be floored by the difference, but you will come to enjoy just how subtle they are in improving your listening experience, and they are now going to be my main speakers for a long while now.