Short of changing the bottom end, high lift or even wild cams, changing the injectors, basically a engine swap i doubt you will get much closer to 120.
Unless you pay for it to be put on carbs, and even then the risk of it snapping the manifold consistently is pretty high. I would concentrate more on getting it cosmetically right, and how you would want it before touching the engine, then you may well be a few years older and have enough cash to get a gti, or do a complete engine swap.
Oh and by the way, ignore yellow, he doesn't know much, and is generally consider a dick on this place.