The seats are very similar in style to the stock seats and have a larger range of adjustments available. These are the seats...

I ordered the special Fiat adapters but in the end, I didn't use them. Instead, I used the new rails that came with the seats and bolted them directly to where the old rails bolted. Well, almost. The rails didn't exactly line up (hence the reason they sell the adapters, but the adapters added too much height to the seat). So I had to have two tabs welded onto the rails closest to the center line of the car in order to make everything work.
I think they look great and they feel great. Fair warning, though, they do sit you about 2 inches higher than stock, which could be a problem for medium to tall folks (and a blessing for the vertically challenged).
Here are some pictures of the seats installed.....



A problem I ran into was that SCAT does not offer any kind of shoulder belt guide and the spacing of the headrest posts are different than the spider's stock seats so the wire type belt guides sold by AutoRicambi wouldn't fit.
I have zero welding skills (I mostly work the wood). I could have gotten a local welder (like the one I used to weld the tabs onto the seat rails) to fabricate a wire one, but he (and a few other shops) weren't interested in such a small, one-off project. So I figured I would make a set of guides using my primitive metal working tools (hammer and vice) and limited metal working skills (ie none).
I started by buying a 4 ft length of metal bar stock from my local hardware store, rounded the edges with a file, and simply bent it into a shape I thought might work using the hammer, vice, and brute force method. A few iterations later (my version 2's are always much better than my version 1's) and viola, a master piece......

You need to really zoom on the closeup picture to see the important curl within a curl.

Holes were drilled for the headrest posts and a frantic search was on for grommets. 6 stores later, I had the grommets (they're an odd size, go figure).

The pieces were painted a satin black with a rattle can, but seats are a curious mix on the spectrum somewhere between flat and satin. After a few failed attempts using multiple rattle cans an "ah hah" moment emerged.....prime the things with black satin and finish them off using SEM dye, which I had used to change the back seat from tan to black long ago. Of course, I had none left and the nearest can was a 45 min ride away in each direction, but a nice day and a hard drive with the top down are what these cars are made for, so off I went. The color match is perfect and the shoulder guides simply blend in.

That's my story and I'm sticking to it.