use grade 8 bolts... and some 3mm thick steel. bolt your stock brackets to the floor, center your seat on them, and cut pieces of steel that will go from the bolt holes on the seats to the bolt holes on the stock rails...
Step by step for you:
Unbolt your stock rails from your stock seats.
Bolt them back onto the floor.
Unbolt the Integra rails from the Integra seats... throw them away. (Not literally... but set them aside.)
Center the Integra seats on the stock rails
Measure with something from the bolt holes on the rails (where they came off the seat.) to the holes on the bottom of the seat pan.
Cut some 1/8 thick, 1-2" wide pieces of steel at 1" longer than you needed it, round off the square edges.
Bolt them to the rails, using grade 8 hardware, then to the seat, using stock seat mount bolts.
That's as good of an explanation as you're getting from me, this is how I usually do it, and it still passes DOT inspection.