Tuning a naturally aspirated engine - more specifically a small displacement naturally aspirated engine is quite a technical exercise. There are many unfamiliar concepts that form the basis of this type of tuning which one needs to understand if they are to extract any significant gains beyond bolt on modifications.
Assuming you are not an engine builder, it would be better value to swap for a 1.8t whether this be an engine conversion or selling up: the latter being a lot less problematic with insurance and less effort. It's pretty surprising how cheap the 1.8t variants are now.
