I know what you mean that's why I have switched to a hybrid, quite a good improvement from standard with the stock hardware. I would dial back the requested a bit if it's unable to meet the specified by that much the pump must be truly maxed out. In my experience it seems you can usually get 30-35% gains easily with a map and a few other tweaks. 50% comes with a turbo change. After that it starts getting quite expensive and not where most people would be going. But you would know that anyway after your Golf Build. Looks like a hybrid and a HPFP on the list if you want any further improvements.