Well, this firmware version doesn't cause tons of wireless download problems when QoS is enabled, at least. So, I'll be sticking with this firmware for now.
I'm not using a UPnP server with Broadcast support enabled in VPN, so I can't comment on that issue.
Under TX Power, it now states:
"FCC channel 34~48 max: 50mW for North America.
FCC channel 149~165 max: 1000mW for North America.
ETSI max: 200mW for Europe, South America and APAC.
The real Tx power is automatically adjusted due to regional regulatory. "
5GHz Transmit Radio Power adjustments do appear to work as expected with this firmware.