It all depends on what one wants and expects out of a swap/build. I have three different Alltrac projects going (No comment, that's a different story :doh: ).
After some research, I have my ST185 with an ST215 Caldina swap (on going), (waiting on the wiring to get done). I may later go with a turbo upgrage, AEM FIC etc, but for now, I wanted a BPU+ set up. I wanted some newer technology, lower mileage and reliability. I felt like giving it a try, so I went for it. I will eventually post my progress soon on this swap in the Projects section.
I have an ST165 with a built ST205 set up (pistons, rods, MLS gaskets, ARP all over), along with a big turbo, fuel system upgrade, side feed entry intake manifold, EMS for more power. Some could argue I could have done the same to a 165 or 185 motor, but what's done is done. That's the route I wanted to go with this car, and we'll see how it all works out. My goal is Mid 11s in the 1/4 mile, and respectable and fun track times with it. Posts to follow as well.
Then comes the "hybrid project" coming up (Not sure why I call it a "hybrid" since it's all 3SGTE, just a built bottom end 1st gen block). I found a relatively clean local ST165 (in a color I've always wanted), plus I had so many parts laying around.
So far, built ST165 bottom end (that came from my ST185), and a complete 3rd Gen head along with EMS (I have an SDS EM2-F ems, but may go more modern AEM EMS4 or DIY auto tune), TD06-20G turbo etc. The reason for this was an abundance of parts, and I just thought I'd give it a try. I was initially going with another Caldina ST215 swap, but decided to use the parts I have laying around. We'll see how it all goes. I'm also going EMS, because by the time I find harness and ECU, I could have my own clean unit built with a programmable set up that'll control boost and many other things. Keeping it simpler than chasing harness, ECU and having to pay to make it work, when the EMS is light years ahead anyways.
Everything's a gamble. From rebuilding a 20+ year old motor, to buying a "low mileage" JDM motor that may show low mileage on paper, but not show all the abuse it went through before being yanked out and sold to us JDM crazed Americans.
Just buying a 20+ year old rare car is a gamble, so do what works for you.
OH, to add more fun (and misery) to the stable, I've been eyeing a late 90s Corolla fwd sedan for a 3SGTE swap (One of the many engines I have laying around). In 100 years from now, none of this will matter, but I'll be damned if I don't enjoy doing it now.