How wide is too wide?

well too wide can have adverse problems with weakening things, as your end up with a lot more leverage on parts
the farther out the more stress it adds to things
do you plan to want to run spacers or how do you want to make things wider?
and HOW wide are you wanting to go?
when you go taller in tires you actually raise the center of gravity some too, so keep that in mind

if that is already 5 inches wider than stock, is it done with off set and spacers already or???

I don't think I would want to go any wider than the 5 inches you state its at now, as its would I think add a lot of stress to parts
Before I would make wider spacers I think I would just add a dual wheel set up like deal, all around,
but that will end up robbing a TON of power, and a Gear reduction for sure to do any serious riding IMO