have you done the tube connectors/no rez upgrades as well ? If not, for slightly less $ as those 4 27uF sonic caps will run you, you could get a couple sheets of no rez and a set of tube connectors, I bet you'll be surprised at the diff they make. If you go with the tube connectors at some point, remember to order a couple extra male ends for your speaker cables.
I don't know what AV123 put inside the cabinets (if anything ?), but it may also be worth while if/when n you line the cabinets with no rez to try adding 1 - 1.5 oz of acousti Stuff behind each driver . Fluff it up and cover the rear wall evenly. You can get it a PE or Amazon
Just some sugggestions