Also, what model Firetide APs are being used and are they being powered over the ethernet or from AC power? From what I've seen they are all mostly 802.3af, while the 175s are 802.3at. The higher power may exacerbate the issue (if it's power filtering related). If the firetide APs they have seen work before are 802.3af and 10/100, while we are 802.3at at 1gig, it's not apples to apples. I'd be curious of the functional differences between the Firetide devices the vendor claims are without issue compared to the 175s, to see if it's more medium related.
Do you happen to have the make/model of the surge devices used by chance?