same, just what people call em.

technically they T3/4s like RS500 turbos are. Ie T4 compressor and T3 exhaust side.

but they got the name T35 as they too big to seem like a T3, and too small to seem like a T4.

and call T38s that for same reason, but even closer to a T4.

and like mentioned, RS500 "T4s" arnt real T4s either.