My seats came with those sliders. I wanted to be as low as possible, (I have a Spyder) so I ditched them and bolted the rear of my seats to the floor and raised the front with spacers.
I wanted to minimize the holes drilled in the floor, so I mounted some flat stock to the bottom with a few holes in the rear for future adjustments. I just had to drill two new holes for the front since I was using the existing rear holes. This leaves me with just two unused holes, but having some holes in the floorboard is good for drainage.
Maybe one day I'll replace that stack of spacers with a nice peace of wood or aluminum. I also did the same to the passenger seat.