I can't imagine how off the balance is on that thing. I've had quite a few extended magazine shotguns, and always found them "nose heavy" and "hard to get on point quick".
As a result, my Benelli M1 Super 90 has a 1 round extension.
If I need more "firepower" I won't be grabbing a shotgun...it'll be my FN SCAR.
My shotgun is for home defense against the meth-addict looking for drug money or the coyote looking at my chickens. For anything else I'm grabbing either my 5.56 or 7.62 FN Scar.
(Yes, I have both calibers and they are awesome).