mods to do before tune

[BJ]

Changing just the cats made almost no difference, about 1kW.

This is the closest thing I can find, but you need 2 1/4 not 2 1/2.

http://www.ebay.com.au/itm/High-Flow-2- ... 415e2b688d

http://www.ebay.com.au/itm/2-5-Metal-Ca ... 4cf8c9cd13

[kleinerbastler]

These cats are only EuroIII standard, so that´s the reason of CEL. I think that your GenIV has similar emssion standard like EuroIV here in Europe. To reach this standard you have to put in 200cpi cats. In Europe if your reach a lower emssion standard than OEM, you have probs because of tax evasion and you are no more street legal. Don´t buy cheap cats, you will pay twice.

Ingmar

[Rome_BRZ]

These cats are only EuroIII standard, so that´s the reason of CEL. I think that your GenIV has similar emssion standard like EuroIV here in Europe. To reach this standard you have to put in 200cpi cats. In Europe if your reach a lower emssion standard than OEM, you have probs because of tax evasion and you are no more street legal. Don´t buy cheap cats, you will pay twice.

Ingmar

I somehow doubt tax evasion comes into this

[kleinerbastler]

I wrote in Europe as an example, because some taxes for cars are calculated from the emission standard level and displacement.
But don´t reach the OEM emission standards is maybe not legal in your country too.

[Rome_BRZ]

I wrote in Europe as an example, because some taxes for cars are calculated from the emission standard level and displacement.
But don´t reach the OEM emission standards is maybe not legal in your country too.

Oh that makes more sense!!

[Tradewind]

I wrote in Europe as an example, because some taxes for cars are calculated from the emission standard level and displacement.
But don´t reach the OEM emission standards is maybe not legal in your country too.

Correct for Australia for sure