Not having a go at you mate, but with mr2's there rarely a quick or cheap fix to get it back on the road.
You need to sort out your goals and then work your way backwards.
- If you want a high HP MR2, then a gen 2 engine block is not really that much different to a Gen 3 - mainly because everything is getting changed. And it would also be simpler as you don't need to change looms, speedos, etc. So if this is the case, the rebuilt engine for 4k sounds good. Slap it in, then add turbo, fuel etc, as you know it has a built bottom end.
- If you want a reliable 200rkw mr2 (still quite quick) then a Gen 3 with small bolts on (intake, boost controller, exhaust, timing, intercooler) will be your best bet. Only problem is you need to re-pin loom, change speedo, etc. Which...isn't that hard, and you could probably do yourself. I did mine when I was still at school :)
I suggest build your gen 2 then modify to suit :)