Hey man.
Congrats on the LSs. I have had a pair for a few years now, and I would like to delude myself into thinking that I am an expert on getting these speakers to sing to their maximum potential.
I have been through the ringer with these things trying to get them to perform well in my 13x18x8 room, and it has taken a lot of patience, and a good amount of mistakes to get them sounding like everyone said they should.
For the record, mine were initial from AV123 as well. Now, the only thing AV123 left, is the cabinets, and the drivers.
In terms of the No-Rez, AV123 had did a pretty poor job of installing the No Rez in my speakers. They used as little as possible, and didn't clean off the side of the cabinets very well causing a similar issue to yours with pieces falling off. I wound up just buying all new slabs of No-Rez from Danny, and fixing the situation. I used Behr Floor Adhesive remover to get the gunk off the sides, and then cut all new pieces of No Rez where needed.
If you don't want to purchase new No-Rez because it is expensive, I am sure that a nice tube of the multi-purpose Gorilla Glue would do a well enough to keep the No Rez from falling back off the walls. I am sure other people can chime in here as well. I would think the most important part would be cleaning off the walls of any goo that would block adhesion.
For what it is worth, the outside of my ports are glued to the enclosure. IIRC, you can remove the tube from the inside of the speaker, which I believe is normal.
While you are in the enclosure fixing the No-Rez, I would buy Polyfill and stuff the cabinets with them. You can buy PolyFill at Walmart for pretty cheap, and when you stuff the speakers with them, in combination with the No-Rez, the bass and the lower mid range will clean up extremely well. I would recommend this highly, since it is cheap and easy to do.
Once you get the No-Rez and the Polyfill in, I would certainly look here,
http://herbiesaudiolab.net/spkrfeet.htm .
The Giant Fat Glider, since I was provided with ZERO spikes from AV123 (honestly was luck enough just to get the speakers), did wonders for cleaning up the bass. They also make the speaker easier to move along the floor. If you already have spikes, Herbies sells a version of the gliders that accept spikes.
These are probably the most inexpensive upgrades you can do right now.
Obviously, after this point, you can get sucked into the world of room treatments (if you do not already have some). The LSs make some serious bass that can overload a smaller room quite easily, and ruin all of the detail, soundstaging, and naturalness they are capable of. I have 21 bass traps in my small room, and still experience incremental improvements each time I add more.
If you are really feeling froggy, there is also crossover upgrades available as well. Since I have zero soldering skills, I had Bill Baker of Purity Audio make me some crossovers from Danny's design using higher quality parts then what were in the original crossovers.
Danny, sells an upgrade kit for the crossovers, which I think are just bypass capacitors that are supposed to make a very nice difference for not a lot of financial outlay.
Good luck with the speakers man! If you have any questions, I am sure that Danny and others will be here to help you. Of course, you can feel free to PM me, and I'll do the best I can to help you out.
Take care.