I'm glad it works for you, but it's unusual. I doubt it sounds muddy though, raising the X-over point shouldn't do that, a crappily designed box might but that's not what you have.

I can get the same "warm effect" by simply turning up the bass, and it sounds to me like you're basically doing the same thing... By nature a little extra bass sounds warm, and most people prefer it. Some old-timers (Clark and Navone) did some tests with musicians setting an EQ where they thought their own music sounded best, and it was always ramped up at the lower end through an RTA.

I would be very certain that your front main speakers are not also crossed at the same point - that would sound horrible. Instead you just have a whole lot of overlap, right? I've heard other people run that way, because they didn't know how to set the crossovers in their amp (NOT accusing you of that). Yeah there was extra bass, and to me it sounded bad, but I don't like rap And it was also pulled to the back of the car, playing something like Korn where the singer has a deep voice was funky - not only did the voice image travel all over the place, but certain ranges of it were way too pronounced where the subs duplicated what the front speakers were playing.

I'm not going to say your system sounds bad - I haven't heard it. In my experience though, I like the front speakers to play as much music as possible, and the subs to play only the very bottom end that they can't handle. I use equalization to make it sound "warm" and accurate and everything else, where needed, and as little as possible.

If you like it, that's all that matters. Everything is worth trying out I guess.