My friend has an 02 accord with some transmission issues. I've read they're pretty standard. He is considering converting from automatic to manual and... I don't see why not? The conversions and transmissions in my area are wildly expensive. I have a buddy who told me the old 2.9 ranger transmissions are compatible with the 3.0 J30 trannys. Is that even a real thing?
I'm not sure about he Ranger but my daughter has the 2004 Accord with a manual and it has been bulletproof with almost 200k on it. I can see why they want to swap the auto for the manual for those years, the accord had quite a few issues with the auto in the 2000s.
As far as transmission compatibility for the ranger/j30, you'd have to do a bit of searching on that.
https://www.therangerstation.com/forums/index.php?threads/2-9-with-3-0-tranny.49594/
"3.0 trannies only bolt to 3.0 motors i believe. you can use any trans from a 2.3, 2.9, or 4.0 and the bellhousings should be the same."