Here's the run down in differences:
SPL tie rod ends use 5/8" (~16mm) chromoly rod ends, Kazama/NAMS use 14mm ends. You can purchase optional bearing seals for the SPL tie rod ends as well.
Construction wise the SPL tie rod ends use steel buckle, 5/8" chromoly shank with 1.25" diameter super duralumin spacers. NAMS is all steel construction. Kazama uses aluminum buckle, steel shank.
SPL tie rod ends are 4 way adjustable for bumpsteer. NAMS is 1 way adjustable. IIRC Kazama is also 1 way adjustable...
SPL tie rod ends have the longest adjustment range on the market, here is a comparison at max adjustment (NAMS vs. SPL):
