I appreciate the info, but digging into my harness isn't something I want to do.. PLus, I have a 10 month old, I don't have the time to source parts and put everything together.. That's why I was thinking of the infotainment deal.
For the RA3/RA4 upgrade (and possibly the carplay as well, I didn't do that so not up to speed on it), The "Harness work" will be the same whether you do the "self install" method with
@Mpgrimm2 's harness or buying from Infotainment - It's plug an play for both. But I get it the other reasons you stated are valid as well of course. I've been happy with the Infotainment setup, so if you decide to go that route you won't have any issues. Ask about trading in your old unit that will save you a bit, and if they offer a Mil discount as well if that applies. Also it's nice in that you place the order, everything comes in a single box and you can be up and running within an hour or two of opening the box, plus having the warranty.
USB should stay the same, ie no changes required there if you do RA3/RA4. I think with Carplay they might be some differences, but check the threads mentioned above, or ask Infotainment.