Well, I can't afford to get an Icom IC-705, but those that have, have asked me how to do a MARS MOD to that rig. Not done so to that rig myself, (Yet...), I did a Startpage Search on the subject, and the most descriptive one that I've come upon is this one.
https://www.prc-77.com/2024/04/mars-modding-ic-705.html The dude who wrote this does also mention MODS.DK, my original 'go-to' on MOD's, but I like how he meticulously lays it all out. So, will it work? I leave y'all with that responsibility on that one, as I pass the INFO on it, but I can not vow that this will actually work. (There, my disclaimer.) The newest rig that I've MARS'ed it, the Xiegu G90 SDR. So easy there, an SMT diode, with an arrow pointing to it. All my other rigs are older ones, with MARS done, for opening up the 60M, 5 Channel, Amateur Band. Well, except my Kenwood TS-2000X, AES did the MOD, but didn't tell me. Oh BTW, if you do successfully do the MARS MOD on the IC-705, there's a possibility that the auto-tuner may not work well on MARS FREQ's. I say that, since the TS-2000X's auto-tuner gets confused on 60M, wanting to toggle from 75M and 40M. The same with the companion auto-tuner for the TS-50S, the AT-50. Pure speculation on my part here, but it can't be bad speculation. Good luck!!!!
UPDATE: Not confirmed, but apparently, those that have the Japanese Version of the IC-705 have to do a different procedure. Can anyone confirm this?