Adding a sub for existing system

I have an M&K system, with a V1250 sub. We are moving into a new home and I am seriously considering adding a sub for more bass, or more even room response throughout the new room.
I am wondering if anyone has experience adding the LFM-1 or LFM-2 as an additional sub to an existing system.
I posed this question a couple of years ago, as a general query, and got every reply imaginable. All the research I've done does not see a problem with different subs in the same room. But generally not stacked.
I am more interested in those who have actually done it and what your experience has been. I understand I could fall in love with the LFM-1 and sell the 1250, but for sake of argument that is not an option at this time.

I've got a pair of LFM-1's in my rather large listening room. However, it seemed a bit much so I mostly leave the 2nd one off except when I'm wathing movies.

Cheers,

That's interesting, although I was considering the effect of 2 different kinds of subs.
I read something of recently on 'hometheaterforum.com' that advises against that. And also that 2 of the same subs work best in the same location.
In other words, if you find the best location for one sub, use the same location for 2.
I orignially thought having 2 in 2 different locations might actually compensate for any deficiences in response due to the room itself.
Maybe that's not really a significant if one sub is properly 'located'.
Obviously, 2 in the same location will give more output.