in my opinon S14 seats are a pretty good upgrades to the stockers, there also other options like s15, gtr seats but i have no personal experience with them.
S14 seats are great upgrade from stockers but although my 180sx seat looks very similar it holds much better in the corners because of the fabric used. Leather seats are just for looks and will never hold you as well as the fabric upholstered ones.
the s13 leathers get quite hard and have a weird contour around the lower back area that gets kind of brutal for long trips i find. i upgraded to s14 cloth and i don’t think i can ever go back to s13 anything now.
s13 vs. s14
there’s more bolstering, cloth holds you in 100x better than s13 leather, lower back/lumbar area is shaped better (at least for me it is). bang for the buck wise i think you should give these a shot if you’re looking for long distance comfort.