the Zetecis not as practical to swap into a 2nd gen, pony, lx, OR gt. yo umust replace the ECM, wiring, tranny, engine, axles, all that jazz. if you want to swap an SPI into a 2nd gen pony or lx, the stock trans can stay, the same axles can be used, all that you do is change the various sensors that are OBDII dependant, and use the 1.9 sensors.
no big deal really. you dont HAVE to go to OBDII, its nice, sure, but its alot of extra work that can be done later if you wish. the 2.0 SPI and 1.9 SEFI are the same block, all the 1.9 mods will swap over, for the most part, so its extremely sensible if you are tight on cash and need the power and increased refineness from an engien to go with the SPI, not Zetec.
Jason