[ikarinokami]

what happens if a background count exceeds a spirits force. specifically if i cast a mana static with a higher background count than the spirits force, does it go poof or just take negative modifiers? in 4A they went poof, but in 5 it seems it's just now a dice pool modifer as opposed to actually lowering their force.

[Glyph]

I concur.  They have a list of things that do get deactivated/negated by background count, and spirits are not on it.  That's one thing I have to be careful about, assuming a rule is the same as it is in SR4.  Overall, spirits have it slightly easier in background count.  Not that the dice penalty to all of their actions is insignificant, but they used to actually lose Force in background count (which was why background count higher than their Force would disrupt them).

[The Wyrm Ouroboros]

I'd say worse than twice their force, but I woul have put that into effect in 4e anyhow.  And in certain places, such as true mana voids (i.e. space) and perhaps fovae, they simply cannot exist at all, because there's just no magic there for them to exist with.

[Lucean]

They could just sit it out.
If you want to make spirits proportionally weaker in BGC-areas while keeping the ratio (-1 to the dicepool per rating point) you could give them a penalty to their Force equal to Rating/2 and thereby giving you a mechanic to actually send them back.