'Azruss' had done a good post several years ago on how to modify the seats and have them ride a little lower. Turns out, Corbeau completely changed how they make the bottom of these seats - which means I couldn't completely rip off his idea.
Corbeau sells a mounting bracket that's specifically for our cars. They are $100 a piece and are about .5 inches thick. Being thrifty, I decided to make my own brackets.
Went to home depot, bought some 1.5"x.125" welding steel. after some measuring and deliberating, here is what I came up with.
After the bracket was made and test fitted to the seat, I opted to spot weld the slider rails (factory fiat) directly to my newly fabricated brackets.
Also was able to score some new 8x1.25 mm allen head bolts to use to attach the rails to the factory mounts on the floorboards. Here is the finished product:
There was a rear screw that was a real pain to get out on the passenger rail -- I tried dremeling the head, drilling it to use a screw and bolt extractor, nothing seemed to work. Finally I just gave up on it and went on to the driver's side. There a front one stripped a bit, but I used a bigger extractor this time and it came out relatively quickly, as did the whole seat. Emboldened, I went back with the bigger extractor to the passenger side and finally got it after some more work. Happily, none of the receiving threads on that floating loose piece you mention seem damaged so that's a good thing!!
