so ive been sitting on doing this for like two years and finally just did it last weekend. the mars/cap mod on the IC-7300 is dead simple, just a couple jumpers on the main board, took maybe 20 minutes including the time i spent second-guessing myself and looking at the schematic twice. transmit now goes well outside the ham bands which i needed for some emcomm stuff where we sometimes operate on FEMA interop freqs.

while i had it open i also did the ref oscillator mod, swapped the stock TCXO for a higher stability unit i got from a guy on the reflector. havent done a full before/after measurement but the frequency display just feels more solid if that makes any sense, and the guys on FT8 say im not drifting anymore so thats something.

the one thing i did NOT touch was the internal speaker. i know people do the foam mod or swap it out entirely but honestly mine sounds fine to me and i didnt want to push my luck. already had the board out once, didnt feel like tempting fate again with more disassembly.

anyway if anyones been on the fence about the oscillator mod especially, i'd say its worth it. just take your time with the ribbon cables, those are the things that'll get you.

the ribbon cable thing is real. i tore one on a different rig years ago and it was a whole thing getting a replacement, ended up waiting three weeks for a part from japan. now i literally sit there with a flashlight and tweezers and take way more time than i probably need to on those connectors.

did you do anything to brace the TCXO after swapping it? i've heard of people having issues with vibration on mobile installs but i imagine for a base station setup it doesnt really matter. curious what oscillator you ended up going with too if you remember the part number off the top of your head.

yeah the mars mod on the 7300 is genuinely one of the easier ones ive seen on a modern rig. icom kind of made it obvious they intended it to be accessible. the older 706 you had to do some more creative stuff to get full coverage and even then the PA wasnt really happy transmitting way out of band for any length of time. the 7300 seems to handle it fine from what people report, at least at normal power levels.

one thing id add for anyone reading this later -- double check your local regulations before you start keying up on non-ham freqs even with the mod done, some folks get a little too enthusiastic after they get it working and forget that the mod itself doesnt grant any kind of authorization to actually use those frequencies. just saying.