Well, I don't know what a VNT-17 or any VNT turbo for that matter is capable of boost-wise, but 35psi is nothing extraordinary for a highly modified diesel. My neighbor has a Cummins dodge with twin compound turbos and it will easily push 75-80 psi. He uses an oil pressure gauge for boost since no boost gauges go that high. And in the tractor pulling world, boost pressures nearing 200psi are not unheard of. Those guys dump an insane amount of water/meth into the intake to keep temps down.
Anyway, if this guy is spraying enough nitrous in this Jetta, it doesn't really matter what turbo is on it other than possibly from an exhaust restriction standpoint. Nitrous and turbocharging are both forms of artificial aspiration.