1. In my system, the 107's are set as large in the 990 setup; they get the full range signal. LFE channel and the bass from the surrounds and center channel goes to the LFM1+. I use the KUBE that came with the speakers, as they have no deep bass response without it. Also, each KUBE is serialized and tweaked to work with that particular pair of 107's.

With my room configuration I ended up with the LFM1+ in the right rear corner (only place it would reasonably fit). I could detect a "hole" in the low frequency sound field; the system sits facing across the end of a 33'x 17' room and the subwoofer is in one of the corners. Also, at high volumes on particular movies (intro to Serenity in particular) the combined low frequency response of the system was not sufficient.

2. I've only had the LFM1EXs in place since Tuesday night and have had a very few hours to listen to them. I was distracted by a tweeter failure on my center channel (fixed) and haven't had/taken the time to do a proper setup. 1 EX replaced the LFM1+ in the corner and one went out towards the middle of the room (to the other side of the listening/viewing position(s)).
For now, and just for grins and giggles, the LFM1+ is sitting in front of the stand between the center channel and right front. All three are driven.

Bass response from the 107's with KUBE is tighter and more accurate than either the LFM 1+ or LFM1 EX. However, even with 300 watts/channel they don't develop the impact and depth of the EX.

Dark Side of the Moon is a real experience. Mannheim Steamroller's Christmas album (Little Drummer Boy and Carol of the Bells) played at moderate volume (-18 dB) in 5 channel stereo mode is amazing. I've got to try Still Life Talking by Pat Metheney (track 1, about 6:45 in) for the deep bass notes as well as some movies. My time at home will be limited for the rest of the year, so there won't be much experimentation until then.