FT, welcome. The fact that your 94TXH(along with most other receivers)doesn't have an "official" 4 ohm rating is of little significance. Under FTC amplifier power regulations, a unit would have to be driven at the full rated power for at least 5 continuous minutes into a 4 ohm load to support such a rating. This isn't a real-world home listening scenario that would ever occur.
The M80s are slightly above average in sensitivity and average about 6 ohms in impedance over the full frequency range. Your 94TXH can easily drive them to beyond safe listening levels.
