I would think a pipe wrench on it would work, but will prob wreck the housing. The front exhaust down tubes might have to be taken off too. Also, I'd drill the head off that bolt if I had to, before breaking the cover (chips and aluminum pieces=trouble), then pipe wrench off what's left of the bolt, it's long. Might be a good time to convert to a spin on adapter, after you get it apart. Lot's of filter choices with the spin on. I can send you a long list. And, hand tight plus a very little, will just about do it with a spin on filter. The spin on adapter uses the same o-ring I believe, as the old housing. If the Dealer stripped the bolt? It's HIS resposibitity to fix it. I think I have the bolt somewhere, and the cover. You can have it. PM me if you want it.
Steve-o