I removed a sensor on the intake plenum and was able to get pictures of a valve with my borescope. Ford doesn't have any sort of recommendations regarding the intake valves. You can look at my thread here:
https://www.ranger5g.com/forum/threads/carbon-buildup-at-25k-miles-a-short-story.21462/...
I agree that Port and Direct injection is an upgrade, but I don't think the 2.3 really has any issue with direct injection only. I've checked the valves on my 21' ranger twice now and there was little to no accumulation at 50k.
I've got the 2.3 in my 21' Ranger Tremor. It's been very reliable and has proven to be a great engine for towing/hauling. It has no problem towing 7500 Lbs. Right now I've got 60k miles and haven't had any powertrain issues.
