Hey Jacob. Do you have an extra SAZ-3000D heatsink laying around? I have thought about taking a 50.4, an new 100.4D and a new 125.2, and robbing the input board and faceplate from the 100.4D, put the 50.4 inside first, with the new 100.4D input board, and take the 125.2 and put it in there converted to a mono amp for the sub channel...
LOL, that is ALOT of work just to have a Sundown 5 channel... Just use a 50.4 and a 125.2 or SAZ-1000D for your sub channel and you got a nice compact setup.