The fourth gen seats are pretty much the same as the thirdgen GTA-type seat.
The headrest are different.
That's why they interchange.
When a new generation is made, they try to use as much as they can from the other generation.
Now, about other seats.
Alot of people get the early Fiero seats to use, as they came with stereo speakers in the built in headrest.
Something to think about.
George