We developed an insert that welds into the floor/tunnel area. This insert adds almost three inches of floor space to better mount your seat. Most seats in Miata's are mounted off center or crooked because of interference with the tunnel. Rather than beat the tunnel with a Big hammer, you call install this piece in about 30 minutes and get the seat into it's proper position. This piece fits perfectly, it is even relieved in the front for the exhaust flange. It is a very easy install. You simply mark the floor/tunnel, then cut the floor out with a jigsaw or plasma cutter, lay this piece on top and weld or pop rivet in place. This piece lays over the factory seams and attaches at the seam of the floor from front to back and at the rear of the floor where the floor meets the rear trunk floor.
This part is not intended to work with a catalytic converter.