FIA certification is largely a joke. If you look closely at the style of seats bearing FIA certification, you'll see a trend of the seats being bolt-upright. That's because testing is done using a dummy held in only by a four-point belt. A seat with any discernible recline will not pass FIA testing without a fifth point because the dummy slides up the seatback when the harnesses move out of place. Until very recently, the FIA did not permit the use of a five-point harness. Long after many clubs have stopped accepting four-point harnesses has the FIA come around to allow five-point testing during seat certification.

ARTICLE 16: SEATS, ANCHORAGE POINTS ATTACHMENTS
AND SUPPORTS
If the original seat attachments or supports are changed, the new
parts must either be approved for that application by the seat
manufacturer or must comply with the following specifications (see
Drawing 253-65) mentioned below:

1) Anchorage points for fixing the seat supports:
The seat supports must be fixed either:
- on the anchorage points for fixing seats used on the original
car
- on the anchorage points for fixing seats homologated by the
manufacturer as an Option Variant (in which case the original
anchorage points may be removed)
- on anchorage points for fixing seats in conformity with
drawing 253-65.
The seat supports must be fixed to the anchorage points for
fixing seats via at least 4 mounting points per seat, using
bolts measuring at least 8mm in diameter.
2) Fixing of the seat supports directly onto the shell/chassis

1) Supports must be attached to the shell/chassis via at least 4
mounting points per seat using bolts with a minimum diameter of 8
mm and counterplates, according to the drawing 253-65.

The minimum area of contact between support, shell/chassis and
counterplate is 40 cm2 for each mounting point.
3) If quick release systems are used, they must capable of
withstanding vertical and horizontal forces of 18000 N, applied
non-simultaneously.
If rails for adjusting the seat are used, they must be those
originally supplied with the homologated car or with the seat.

4) 2) The seat must be attached to the supports via 4
mounting points, 2 at the front and 2 at the rear of the seat, using
bolts with a minimum diameter of 8 mm and reinforcements
integrated into the seat.
Each mounting point must be capable of withstanding a force of
15000 N applied in any direction.
5) 3) The minimum thickness of the supports and
counterplates is 3 mm for steel and 5 mm for light alloy materials.

The minimum longitudinal dimension of each support is 6cm.

6) 4) If there is a cushion between the homologated seat and
the occupant, the maximum thickness of this cushion is 50 mm.

All the occupants' seats must be homologated by the FIA
(8855/1999 standard), and not modified.
The limit for use is 5 years from the date of manufacture indicated
on the mandatory label.
An extension of 2 further years may be authorised by the
manufacturer and must be indicated by an additional label.