At present my system consists of (on a Newage STI MY03)

Downpipe = Prodrive with Sportscat
Decat pipe
Straight through centre section
Ninja Backbox

I see on Scoobyworld you can get the Blitz Nur-Spec R backbox for about £310 or the Backbox and centre section to the decat pipe i've got for £465.

Question.

Is there any advantage in going for the whole system or will the backbox be fine? Ie. for an extra £155 am I going to hear noise change or power gains from that particular part?

 

Not sure mate, I know the Blitz system is highly rated (I have the full system including the Blitz decat pipe from the Turbo), it is stupidly loud but if you have a sports cat you should be okay.

Not sure if it's any different from a Ninja backbox as that is also pretty nuts in terms of sound.

If your already running a 3" bore system then I don't think you will notice any power gains, probably just an increase in sound.