I bought mine from LKQ/car-parts.com. They both show pictures of the vehicles, mileage and vin number. I looked at the pictures and eliminated all 4Runners that looked trashed. (owner prob didn't take care of it). On the engines with low miles I ran the vin through The Toyota.com owners site to see if it had any history. I found one that was listed with like 150xxx miles that showed dealer repairs with like 260xxx so that was a pass.
I found one with 134xxx miles that showed dealer services since 30xxx miles. Oil changes, timing belt, brakes, trans service etc. Looked very well taken car of. 2 owners. I checked that vin on car-parts.com. They had same engine listed for 150$ cheaper. Called them they were part of the LKQ family. So they shipped it to an LKQ in Dallas ( they were in Sacramento) for free. The LKQ shopped delivered to my shop for free too. I paid $1300 about 3ish years ago. Win Win.
If you're not in a hurry that's what I would do again.

PS, the "Taco Toyota" reman from Mexico comes pretty stripped down, no valves covers etc. So there is some work to be done before you bolt it in.

And I think GEARHEAD ENGINEs, where the taco toyo came from, is also part of the LKQ corporate empire.

ALSO,judging by the quality of the 90-$300 balancers out there ( they're all the same), I will be reusing the 280,000 mile harmoic balancer. Replacements are crap.

PSS, local engine shop quoted me "approxiamtely $4000" to rebuild the 5VZ. They don't do many, if any. So I went with the 3 yr warranty at a few bucks less with someone who may knwo their way around a 5VZ.

So far only issue is having to shave down the dipstick to fit in the undersized hole in the oil pump housing.

AS gamefreak says, the transmission IS THE PITA. And having too big hands. EVERYTHING is in a nook or cranny.