I installed earlier versions of Corbeau A4 seats in my '76 Spider. These have a tall headrest, and wide shoulder "wings". There were two big issues. Excesive cushion height; mounting the seats on stock seat rails resulted in little clearance between my legs and the bottom of the steering wheel, and my head hit the top bows. Also, the passenger seat interfered with the side of the car. Spider seats are not symmetrical in the car; the right hand seat is closer to the outside of the car than the passenger seat. My Corbeau seat had to be mounted in the same position since it is wedged between the transmission tunnel and door.
I modified the seat rails to fit in a lower position outside the floorpan mounting brackets instead of on top of the brackets. This, and tilting the entire drivers seat back, has my helmet barely under the top of an autopower "Race" roll bar (this roll bar is too tall for normal convertible top operation).
While the lowback seat might be smaller, I still recommend you do lots of measuring to verify these seats will fit your car in a satisfactory manner
Have any of you installed these? How do they fit? do the side bolsters interfere?
Corbeau Racing Seat: GTA Lo Back