I'm a right in saying that the delightfull burble from a scoob comes from unequal length headers ?

If so would it be possible to acheive a similar note from my 95 fireblade by altering the headers ??

 

1. Basically yes. Horizontally opposed engine plus turbo located where it is plus the unequal manifold (and the ratios between displacement, header diameter, length and so-forth).

2. You'll alter the engine note by altering the headers, most certainly. However, the chances of you getting a similar note to the Impreza will be next to non-existent given that your Fireblade has half the cubic capacity with smaller diameter exhaust tubes and revs to well over 10,000rpm.

Going out of your way to add volume to two of the four branches in your exhaust manifold in this way will be more likely to lose you power than gain it.