I think it depends a lot on the type of recording you like to listen to. If you are into pipe organs, you might be served with a sub that would go lower.
I am not aware of the exact cutoff of the V1250.that is to say I've never measured it..best way is to listen with different recordings, and see if something like the 350 would be better.
I believe you can 'break up' the 750THX system, like use different surrounds, or a swap out the sub.
For now the 1250 in my environment does a very credible job. The impact for HT is excellent and for music, well it is deep and musical. Of course, even going lower might be nice at times, but until you have something to compare it with, I doubt you will think you are missing anything for a good 90% of the listening you do.
I don't think adding the LFM-1 is going to do much for 'going lower' esp. not for the MX-350. But if you are adding a sub for more even room response in a large listening area, or splitting each for a different appliation, like LFE, etc. as curegeorg does, then that's another ballgame.


[This message has been edited by DaleB (edited December 08, 2003).]