ultrabeing

Hi guys I was hoping someone could tell me if this is the correct iso harness for a 1998 R34 GTT to plug into the factory loom http://www.supercheapauto.com.au/online-store/products/Aerpro-Wiring-Harness-APP0120-to-suit-Nissan-1995-on.aspx?pid=224825#Description

When I mean legal I'm referring to the decibels of this exhaust but I was hoping someone could give advice on this as I want to try installing it myself but I don't know much about modding

This is my first car and just imported, I don't know anything about modding but wondering what you guys think about this exhaust and do I need something like a catback or would it already come with it?