I've got a facelift low miles 1.8t aum to replace an ageing agu car. Plan is to tune this to at least stage 1 in the near future. Are there any suggested parts which I should consider swapping across? Seen some suggestions there is a weakness in the pancake pipe outlet on the aum and people seek out the agu equivalent parts. Is this worth doing and would these parts be swappable from one to the other?