Yes GTR's were over-engineered so that they could do that pretty comfortably. GOOD return flow coolers are very rare on a GTST budget, lettuce be real here lots (not all) owners of GTSTs just do basic mods like FMIC, pod and exhaust, maybe a bigger turbo if they're lucky. Not many people do the research and buy a good return flow from the beginning. The return pipe is simply too sharp of a bend, just like how on GTR's the rear turbo intake becomes a restriction because of how sharp of an angle the air has to change to get into the turbo. The idea has reasoning behind it, plenty of cars that can't crack much over the 300kw mark with a return flow when they should be making more, but at the same time, plenty that do make more power with a return flow, but they definitely can be a restriction.
The problem with the metal intake pipe (this is a good part of why I sold my GTST), is that it still isn't legal, even if it was same dimensions and looked pretty much the same, it's still an intake modification. Then when you get EPA'd and you have a bigger turbo inlet that won't accept the standard intake pipe, what do you do then?