what this site has knowledge wise. It's just been covered so many times why an NA really isn't worth putting money into. If you were going to invest 15K into a motor, why not put it into a TT motor? It makes no sense to waste all that money for a minimal increase of power(minimal compared to TTs). You said it yourself you love Z's whether they are TT or NA. I realize that my Z isn't worth putting any more money into in its NA form, so I'm doing a TT swap.
Don't know what else to tell ya bro. Don't let it get to you too bad tho, others have gotten it a lot worse.