Well, it's definitely different than my 810... Fuller sounding too, which I didn't expect. It doesn't cut through quite as well as the 810 and I had to cut the highs pretty considerably to get the tone I wanted and I also had to boost the mids a little to get it to cut through... Strange. I didn't expect either of those to be the case. I also tried both of them at the same time for a little while and it was too much. I had to turn way down and the grit didn't come through like I like it.
Anyway, I'll try it out for another few weeks to get a feel for it. I didn't fall immediately in love, but I've been with the the 810 for almost the entire life of this band so this 215 might just be something to get used to.
Try some dampening material inside, at least the back wall. i have an LDS 215 that cuts through just fine with everything set at flat, with a little bump at 800hz.