Max power?

Your car has a max of 115 hp without any modifications. Hence, it is pretty low on HP. You should invest in trading it for a GLI which is 210hp. (Almost double) because by the time you boost your base engine you had spent much more than the trade. However, if you want to spend money in boosting yours, I will suggest start with a quality ECU tuning upgrade which can give you 60 to 70 extra HP and from there, you can invest in other HP related upgrades such as TURBOS, etc but not even stage III (from your base) will give you what the GLI can provide you as OEM without modifications. Just my opinion. I am pretty sure few folks will disagree with me but those are my two cents.