jap brands tend to use the best pick of piston manufacturers and use specific models, ie the trust pistons i use in the top SR's i build use a crown design and special ceramic coated rings only available under license through trust even though the manufacturer makes "other" SR20 pistons.
Arias are a good budget brand and i use them mostly on budget builds but i am not a fan of dished crown in any HOT SR20 i prefer the flater notched crowns, i am currentley building a test engine with SRP (JE). so i will soon know what they are like.
i dont know of any jap manufacturer that manufactures their own pistons but most are made to spec and are not available in another brand or boxes, they are made under license.