Eh, that difference in weight between the two motors is actually less than a passenger if I remember right. Personally I've always hated that series of GM engines...or 99% of all of their stuff more honestly.
As for lightning conversions... multiple threads for vehicles on different boards showing the poor quality of their conversions. Crushed frames, botched wiring.... the list goes on. If it was one vehicle I might not believe it, but more than one....
The xl7 motors Suzuki made are stout...but poor MPG.
The more I look at the newer Tacoma 4cylinders the more I think they are the best option: good square power, stupidly reliable, light, and the biggest benefit I see is that with the right gearing you should have power for up to 35s while still getting 25mpg.
The problem... the guy I knew of in north Carolina who was a genius with Toyota wiring now rarely does swaps.
A straight axled 4dr with 3-6 inches of additional wheel base on 35s would be about the best semi practical SUV never designed. Better mileage than a wrangler and more reliable while atst being more capable due to a 1500lb weight difference.
1995 4DR Sidekick 16v w/4spd Auto J-Vin 197k
4.5in Low Range Offroad combo Lift
2.25 Piping with Magnaflow exhaust and cat
Many other things...
1996 Geo Tracker 16v w/4spd Auto Canadian 110k
235x75xr15 General Grabbers on Cragar 15x7s
2in piping Magnaflow Exhaust and cat