I'm not curious at all, you
THINK you have a car that has the same gain as the N54. In reality you just added up the quoted, most likely crank, hp numbers. Which is the dumbest thing I've ever heard. Simple as that.
You're probably use to this moronic type of calculation and are going through shock at a community that quotes wheel figures from actual dynos.
FYI the car you described likely makes MAYBE 260 whp while the 335s are making around 350 with just a tune, that's about the same HP/displacement and we're still very early into the engine.
You asked how a 2.0 litre with 10.3:1 could possibly be gaining more than the 3 litre 11.3:1 N54 and you answered your own question with your skepticism, it can't and won't.