History lesson ...:
In previous core series units HB would not recommend the XHS 9 HDSI 180 T (Hi Def SI) for any unit that came stock with the XNT 9 SI 180 T (Compact SI) simply because those smaller SI units were not capable of transmitting all the frequency capabilities of the XHS 9 HDSI 180 T --- specifically the smaller units could not transmit the 800kHz imaging frequency ...
Now to today ...:
HB would not recommend the XM 9 HW MSI T for the HELIX 7 CHIRP MEGA SI because this smaller unit cannot transmit all the frequency capabilities of the XM 9 HW MSI T --- specifically the HELIX 7 CHIRP MEGA SI cannot transmit the 800kHz imaging frequency ...
Now will it work ...??
Most likely ...
Will it be better ...??
I can only assume yes because there are no comparison pix that I've seen ...
Rickie