well man i dont know about the GTi, but i see the GTs all over the place here and 4AGE motors are all over the place, the Pacific North West isnt real good for cars, so there are mr2's and 86 gts all over the place. i run a corolla fx16 GTS,and am always on the look for a 4AGEZ motor thats what a good swap is i dont know what car came with them. but the head is the only diff reall, you can get a block for the 4AGE from all sorts of cars, the 4AC is the same block and the tranny that came in the 4 door corolla is a really quick and good gripping tranny. i dont know where a good place to buy new parts for the 4AGE is cuz most of it is pretty expensive, but you can find the motor in junkyards and on the side of roads all over the place