When does stock air intake become restrictive?

[kapul4]

Greetings, until how much HP does the stock air intake on the Cupra MK2 become restrictive? Can it handle 300hp@ crank without having to go for some aftermarket ones?

 

[Legojon]

I went Stage 1 with the stock air intake and made 296bhp. I added the Revo intake later because I had a bit of spare cash and was planning on getting more power later. It made zero difference. But it's a requirement for Stage 2.