VNT20 is not big for 1.6, I´m running GT23V... Boost is not everything you need.You could try K26 from Mercedes 300 12V DT. It is pretty commonly used here at 1.6 and 1.9.
habba you have some more info about it, boost, 0-100km/h, 400m sprint, rpm range, hp, plunger... ?Greetz, Benjamin