Muzz,

Glad to hear that Grand Prix Mazda at Aspley have been reasonable in their approach to this, and it is all sorted. It could have been way too easy for an over-zealous service person to (incorrectly) blame the cat-back!

I'm glad it sounds the good now! You must have been a little dissapointed to begin with!

Good luck on your wedding day, and may you have many years of happiness.

Cheers,
Hymee.

quick update: drove back down to Sydney (from Bris) after my honeymoon.

This is much more like it! I am know averaging 9.8L/100klm, with G flash and hymee exhaust, never sounded or went better!

You're kiddin' me....that's about 28mpg!! Unreal.....Enjoy :)

I started suspecting the CAT my self.
When the car is cold the car is not "breathing" ok and I have a very very bad smell (like gasoline unburned).
When the car warms up and then drive for 10-20km and then switch off I have those creaky noises under the car (coming from the CAT).
Are these noises a sign that i am out of CAT?
And another question is how is connected the performance of Catalytic Converter with the performance of the Ignition Coils?

I do not know if it is related to bat catalyst but I have checked my car with an CANSCAN and I have seen that the diagram of oxygen sensors is fluctuating whereas in another RX-8 with a new cat the diagram does not fluctuate. Always this comparison was done at idle.

Do you see any problem with the fluctuating catalyst diagram at idle?

Well...
CANSCAN (and any other OBDII) is the one option I have to check whether my cat has gone and the other is to take it out inspect it and through it away cos i am almost convinced that is the catalytic converter.
This article helped very much to understand the situation
http://rotarynews.com/node/view/164