Ok I dont have a ton of bass heavy music, but I do have the Grammy nominees cds from 2009 and 2010. I tested with Apologize from one republic, I kissed a girl- Katy perry, from 2009 and poker face - Lady Gaga.

I used my Checkmate cm-140 spl meter C weighted and turned up these songs to 100db. which is about all I can take. The XPA-2s meters were peaking at 8 blue LEDs out of 12 I cant remember how may of the twelve are red? Maybe four. This is with the sub removed.

My findings are IMHO that the bass is not as strong as I would like it. The mids and highs sound more strained then they do with the sub/crossover turned on. The m80s are easier to listen to at these levels with the sub on. I am not hearing any glaring distortion they are just more harsh/a little strained sounding. At these levels the bass is starting to bottom. It sounds like I am reaching the limits of the woofers. I could drive them harder I think but I don't want to damage my equipment or ears.

For me these heavy bass songs sound way better with my sub. The highs and midrange are crisp and clear. And the bass output is much stronger as expected.

Not sure if this helps just my observations.

M80,VP150,QS8,ERD-1,XPA-2,XPA-5,UMC-10,PS3,XBOX360,Dish VIP622,PB13 Ultra,Panasonic PT-AE3000U