Sure, I'll weigh in a little.
Don't know everything, but have learned a little after all these years with the NSX.
Refresh and rebuild are pretty much the same thing. Just depends on how far you go HP wise and what parts you use.
Both require the cylinders be be honed or bored to get rid of the oval-ing caused by time and heat which will include new pistons and ring packs. Other things that get replaced are the bearings, rod and crank, head gaskets and new head bolts. At the same time the block & heads are sent out for resurfacing, heads are gone through, valves, guides and springs replaced, should be anyway if done right. Then everything is put back together with new timing belt, water pump, oil gear & housing, gaskets, O rings and hoses.
Refresh, replacing what you currently have in its pretty much stock form.
Rebuild, replacing with upgraded parts, closed deck or floating sleeves, upgraded parts throughout, specialized boring and piston sizes way beyond stock, etc.
Both require balancing, bearing clearances set, etc. There's really not a whole lot of difference other than the money you spend doing it.
Whether or not you dive into the bottom end really matters on whats going on the with motor at the time. Is it burning oil, is it using water, leak down and compression numbers, etc.
I've seen many motors with 150,000+ miles on them that don't burn a drop of oil and tolerances are still tight when cylinder holes are measured. In other words, rings are still sealing around the cylinder walls. You have to remember than even though cylinder holes go out of round, the rings wear to match them. So just because a cylinder might be out of round doesn't mean the bottom end needs to be rebuilt. Burning oil, smoking or a lot of blow by are indications the rings are no longer sealing which means it's time to refresh/rebuild the bottom....and sometimes that can turn out to just be the heads as well.
Most motors if taken care of really don't need much other than the top end being gone through. Heads, gaskets, WP, TB, Gaskets, O Rings, Oil gear and housing, etc. But again, it all goes back to whats going on with the motor and what your end goal is.
Regan's motor was a perfect example of not needing a complete refresh/rebuild. Because he has taken such good care of his motor, oil changes continually, not letting it over heat continually, servicing it as required and not over boosting a stock motor, there was nothing wrong with his bottom end, even though he's tracked the hell out of it and driven it many miles on the street. As a testament to that, as he says, we did only the top end 3 years ago, he's still tracking it, still putting miles on it driving it on the street, 25,000 miles have gone by since, and it's not burning any oil and still running strong. Regan's motor actually uses head bolts, not studs, and yes, I torq'd them to 70 ft pds because his motor is boosted. He has a 3.0 block, which allowed this, whereas a 3.2 block should be time certed before switching to head bolts instead of using studs and torq'd to 70 lbs, since I found the 3.2 blocks are weaker in the threads and don't do well with higher torq for boosted motors if changing over to bolts.
All of which is just my opinion, for what it's worth
...and thanks Regan, I very much appreciate the confidence you have in my work and the fact you would say so.
Btw, Coz rebuilt the top end on my 3.0L. I have high miles as well. I track the sh*t out of this car and i'm not apologetic about driving this car hard. With Cometic head gaskets, stock compression, OEM head studs torqued to 3.2L spec, 3 angle valve job, etc but all components basically stock... after 3 yrs it's still pushing strong at 8psi of boost. We made the conscious decision not to touch the bottom end except for swapping out the oil ring gear to a JDM brand. Can't thank Coz enough for the TLC. 3yrs and probably about 25k miles and GOING....
Maybe Coz can weigh in if he feels like it.