Thanks guys, loads of great info. Whilst I love the side pipe look I am loathed to have holes cut in the side of her, what with her history! Looks like its guna be the quad system, can't wait!

Matt
I understand your decision Matt, but don't rule out the sports ovals, they do look and sound great.

Today I took some photos at the works, just showing the standard rear silencers and the side-pipe installations, as follows.
The pre-cat common to both systems:

Exposed side-pipes:

The circuitous route round the rear suspension of the rear exit exhausts:

The standard tail-pipe before fitting:

It makes you wonder why one can't just remove these rear silencer tips and just continue the exhaust pipe to the rear of the car with some un-silenced exhaust tips, as the side-pipe exhaust does without this extra amount of silencing, and back-pressure.
Maybe one of the more technically minded members can give an opinion on this.