i am really wondering what to do. i have a 94 sammy tbi, with the stock 1.3 liter that is shot. i dont know which engine to put in, the 1.6 16 valve or the 8. i want to do as much of this as i can so which one do i go with? Dont you, with the 16 valve, have to change the ecm or ecu, as well as the wiring harness? And with the 8v cant you basically "drop it in." any help on this subject would be greatly appreciated!

Neither are simple "drop-in" engines.  It isn't an incredibally difficult swap but you need:

an adapter kit consisting of motor mounts and an engine/transmission adapter plate

the entire engine wiring harness and ECU for either engine including the VSS sensor on the back of the donor car's speedometer.  Adapting the new engines' wiring harness to the Samurai will take some patience.  If you have none to spare, there are vendors who can provide you with a modified wiring harness.

You can swap the intake and the distributor from the Samurai to the 8-valve and be good to go but most folks either keep the TBI system or the MPFI system - depending on the engine - or go with a non-computerized aftermarket carburetor system in the case of the 8-valve engine.

I hope that this helps!

PS:  The search engine is your friend here...