So, what are you wanting to do? Utilize the ED30 piping? And "Piping" meaning what exactly?
Are you wanting more power? If so, research the power of a tuned MK5 GTI and that of a K04 swap in a GTI. Decide on that and then we can help. A highly tuned K04 swap will require the hpfp internal upgrade and results in replacing the cam follower very often, a K04 turbo, either the S3 or RS4 injectors(depends on which your tuner you decide on prefers), the tuner usually requires an intake and down-pipe, and usually an FMIC upgrade is optional per tuners. All of this and the tuning. Then you may find it would fare better with upgraded brakes and suspension.
Otherwise, you could just tune the oem K03. You could do so with just an intake(not needed really) and a downpipe. You can take it a step further and do the hpfp internal upgrade and again deal with frequent cam follower changes. Then tune it accordingly...K04 tuned or K03 tune for the hpfp upgrade.
But yeah, decide on the power you want and how far you are willing to go.
If you are new to the MK5 GTI with FSI engine and aren't familiar with its flaws;
first thing to do is remove the hpfp and inspect the cam follower and tri-lobe of the intake cam. Test for leaks in the pcv and its tubing. Have the error codes read and look at its real time data for boost and fueling. Also, have a look at its fuel trim data. Place a request for help on this forum stating you need help from anyone nearby with VCDS that would be willing to help you with all of this. Or; purchase VAG-COM cable, download VCDS for free, and learn how to look at data yourself. This is my advice for one who wants to learn to self diagnose issues and understand when looking at its data. Good luck.