So I had my brother change the still original factory exhaust system to a free flow one. The pipe was a dia60mm and I left it like that - no need to change to a dia63mm. He took out the catalytic converter and replaced it with a resonator. The large middle off-center box was changed to a free flow one but he left the small back box as is seeing that it is a free flow box already.
Traveled 650km with it today and can say that:
*Better drive-ability through the lower rev ranges - it feels a bit more lively and responsive
*Seems like the fuel consumption also improved somewhat, but will confirm as the weeks go by
*There is a bit of a "growl" when idling (which sounds nice

) but no difference when accelerating or driving.
*The exhaust fumes do smell a bit more now that the catalytic converter is removed
In my books an improvement.