Terraclean is a waste of time on a direct injection engine, just buy a fuel cleaner that goes in the tank if you want to 'clean your injectors'.
A Full PCV delete is the only thing that will really help (R-Tech sell a kit that Vents to atmosphere). Catch cans still recirculate hot oily vapor and tend to mainly catch water vapour from my experience on the TFSI. You will still get some build up that seems to be from the valve stems but that shouldn't be much.
WMI alone was proven to not be 100% effective on keeping them clean, and certainly won't tackle any hardened deposits. Manual clean, full PCV delete (not the £45 ebay jobbies that just remove the front PCV valve and force everything through the rear breather in to the turbo) and WMI are what you really need if you want to keep the inlet clean